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Aviation Reports – 2010 – A10Q0087

| Transportation Safety Board Reports | July 2, 2012

Transportation Safety Board of Canada

Aviation Reports – 2010 - A10Q0087

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Collision with Water
Lake Buccaneer LA-4-200 (Private), C-GGFK
Lac Berté, Quebec
03 June 2010

Report Number A10Q0087

Synopsis

At approximately 1900 Eastern Daylight Time on 03 June 2010, a privately operated Lake Buccaneer LA-4-200 amphibious aircraft (registration C-GGFK, serial number 1082), with the pilot and a passenger on board departed on a visual flight rules flight from Lac de la Marmotte II to Baie Comeau, Quebec. The 98 nautical mile flight was to take approximately 1.3 hours. When the aircraft did not arrive at destination by the end of day on 04 June 2010, a search was started on the morning of 05 June 2010. Using sonar, the aircraft was located on 26 June 2010 by the Sûreté du Québec police dive team at a depth of 230 feet in Lac Berté, 5 nautical miles south of Lac de la Marmotte II. The aircraft and occupants were recovered on 02 and 03 July 2010 with the assistance of a remotely operated vehicle with underwater camera. The aircraft sustained substantial damage on impact with the surface of the water. The pilot and passenger were seriously injured and drowned. No emergency locator transmitter signal was detected by the search and rescue system.

Factual Information

History of Flight

The pilot and passenger departed from the Baie Comeau (Manic 1) airstrip (CSL9) located 6 nautical miles (nm) northwest of the Baie Comeau airport (CYBC) at approximately 10301 on 01 June 2010 for a visual flight rules (VFR) flight to the pilot’s cottage located on Lac de la Marmotte II2, Quebec, 98 nm to the northeast. The flight was uneventful; having arrived, the pilot reported no technical difficulties with the aircraft.

At 1806 on 03 June, a message was left on the pilot’s home voicemail indicating that they would be returning to Baie Comeau. However, there was no mention if the intent was to return on 03 June or 04 June. No other information was provided in the message. It was not the pilot’s habit to depart after supper time; family members believed the departure would take place sometime on 04 June.

When the aircraft did not arrive by end of day on 04 June 2010, family members initiated a search on 05 June 2010.3 A search by private helicopter was conducted in the vicinity of the pilot’s cottage and other known frequented fishing locations; the aircraft was not located. Search and Rescue Halifax were advised of the missing aircraft and deployed to the area. On 05 June 2010, debris from the right wing auxiliary fuel tank (sponson) was located on the shore of a bay on the northeast side of Lac Berté, 5 nm south of Lac de la Marmotte II (Appendix A). An underwater sonar search was initiated by the Sûreté du Québec (SQ) police dive team as well as a shoreline land search by family members. The SQ dive team located the aircraft at a depth of 230 feet at the bottom of Lac Berté on 26 June 2010 in the area south of the initial search area. A remotely operated vehicle (ROV), equipped with an underwater camera and robot claw, was used to recover the aircraft occupants and to secure the aircraft to raise it to the surface. The aircraft and the pilot were recovered on 02 July 2010. The passenger was recovered on 03 July 2010, 80 feet from the aircraft location. The aircraft was examined before transporting the engine and propeller to the TSB Laboratory in Ottawa for further examination.

Retrieved Photos

The passenger’s camera was found in the wreckage. Photos extracted from the camera were taken over a 3-day period coinciding with the 3 days the pilot and passenger spent at the pilot’s cottage. The last group of photos shows the aircraft on take-off, heading south from Lac de la Marmotte II towards Lac Berté, and in cruise flight over the tip of the northeast bay of Lac Berté heading south. It was determined that the pictures were taken in the evening because photos show the sun setting to the right, while the aircraft is flying in a southerly direction. This information helped confirm that the occurrence flight took place on the evening of 03 June 2010. The aircraft’s altitude as shown on the last photo (Appendix B) was estimated to be approximately 876 feet above the surface of the lake (2073 feet above sea level). The exact time of the occurrence is unknown.

Weather

The retrieved photos also helped determine the weather conditions at the approximate time of the occurrence flight. The reflection of the sky and clouds on the surface of Lac Berté, revealed that weather was conducive to VFR flight; it was sunny with scattered clouds, winds were light to nil giving glassy water conditions for the lake surface; no thunderstorm activity or precipitation was visible in the area at the time the photos were taken.

A weather study completed by Environment Canada confirms the weather picture depicted in the photos. The study for the Lac Berté area on the evening of 03 June 2010 concludes that the Manicouagan reservoir region weather was appropriate for VFR flight; the sky was generally clear and winds were nil to light at less than 5 knots from the east. These weather conditions remained until the morning of 04 June 2010 and were not considered a contributing factor in this occurrence. Weather was forecast to deteriorate late on the morning of 04 June 2010 due to an approaching low pressure system.

The pilot’s satellite phone indicated several calls were placed on 01 June, 02 June and one on 03 June 2010. No calls were placed to the Flight Information Centre telephone number to obtain aviation weather information. The pilot may have obtained forecasted weather from an alternate source such as AM/FM or HF radio which was available at his cottage. It could not be confirmed if the pilot decided to leave on 03 June 2010 because the weather was forecast to deteriorate late morning on 04 June 2010.

The Pilot

The pilot held a valid private pilot licence since 1975 and a seaplane endorsement since 1976. The pilot had previously owned 2 other Lake Buccaneer aircraft before purchasing C‑GGFK in 1983 and had approximately 2930 hours total flying time; all but 90 hours, were completed on Lake aircraft. Over the past several years, the pilot flew occasionally during the months of April through October, flying approximately 45 hours per year. The pilot had met all Transport Canada currency training requirements.4

The Aircraft

The aircraft, a single engine Lake LA-4-200 EPR amphibious aircraft, was manufactured in the United States by Consolidated Aeronautics Inc. in 1983. The engine is mounted on the top of the rear cabin area in a pusher type configuration. The pilot purchased the aircraft new in May 1983. Records indicate that the aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The last annual/100-hour maintenance inspection was completed on 03 August 2009.

It is estimated that had the aircraft taken off from Lac de la Marmotte II with slightly over a half fuel load, 2 people on board (actual weights used) and approximately 100 pounds of baggage, the weight and centre of gravity would have been within the prescribed limits during the occurrence flight.

The aircraft was not equipped with a flight data recorder or a cockpit voice recorder, nor was either required by regulation.

The global positioning system (GPS) on board the aircraft was a panel mounted Trimble TNL 1000 GPS and did not allow downloading of any flight data information which would have been available to the investigation.

The Wreckage

Examination of the wreckage did not reveal any pre-existing aircraft structural deficiencies. All flight control surfaces were recovered. Continuity of primary pitch, roll and yaw controls was confirmed with no sign of any pre-impact anomaly. Flaps were found in the up position, the normal position for cruise flight. The landing gear was found in the up and locked position, the normal position for cruise, take-off or landing on water. The elevator trim is hydraulically operated and was found in the cruise position. However, since many hydraulic lines were severed, the trim position may have been modified during the impact with the water.

Wreckage of the Lake Buccaneer aircraft on the shore
Photo 1. Lake Buccaneer C-GGFK↑

The aircraft collided with the water at an approximate 20° nose-down attitude, right lateral movement and right wing low attitude. The right wing tip collided with the water first, tearing away the right wing sponson and the outboard portion of the right wing leading edge and wing tip cover (Photo 1). The nose section, from the instrument panel to the nose cone of the aircraft, was torn open from right to left. It remained attached to the rest of the fuselage by the front left side skin, electrical wires and hydraulic lines. The cabin floor was torn apart as the nose section separated from the rest of the aircraft. The seat rails failed in overload as the floor was torn open allowing the seats to come free of the aircraft. The left wing outboard leading edge was flattened as it whipped around to hit the surface of the water after the right wing and nose struck the water. The tail section and top vertical fin of the aircraft also showed kinks in the aircraft skin indicating the aircraft struck the water while rotating around the right wing. The aircraft was found upside down, resting on the top of the engine, at the bottom of the lake. There were no signs of pre-impact fire or bird strike.

The Lycoming engine5 was removed from the aircraft and transported to the TSB Laboratory in Ottawa for teardown. As it was installed on a pylon aft of the cabin and faced rearward, it was protected during the frontal impact of the aircraft with the lake surface and sustained no visible damage. Examination of the engine and accessories did not identify any anomalies that would have prevented normal operation.

The Hartzell propeller6 was examined. The blades were in a low pitch position at the time of impact. However, an estimate of power output could not be determined. No anomalies were noted with the propeller that would have prevented normal operation.

The Directional Gyroscope7 was examined and showed no evidence of impact damage. The gyroscopic rotor mass and mass housing revealed circumferential scrape marks in the base of the housing. The extent of the scrape marks indicate that the mass was spinning at high speed at impact with the water, indicating that the engine driven vacuum pump was functional at the time of the occurrence.

The electrically driven turn and bank coordinator8 was examined. No witness marks were found on the dial face; however an examination of the gyroscopic mass revealed circumferential scrape marks made by contact between the spinning rotor and a protruding wire. For this to be the case, electrical power was likely available.

The dial face of the vertical speed indicator was examined and revealed a pointer edge scrape mark that showed a rate of descent of between 1000 to 1500 feet per minute at the time of impact.

The pilot fuelled the aircraft before departure from Manic 1 on 01 June 2010. The pilot was not in the habit of filling the 2 wing sponsons. When the main wing tanks are full,9 endurance is approximately 4 hours of flight. Five-gallon jugs of aviation 100LL fuel were kept in a shed at the cottage. The aviation fuel jugs’ handles were marked with blue spray paint in order to differentiate them from other stored unpainted 5-gallon jugs of gasoline used for other machinery such as all-terrain vehicles. The fuel stored at his cottage location and marked as aviation fuel was checked for its quality; no water or contaminants were found and the color of the fuel confirmed that it was the appropriate grade for the engine.

Because  the aircraft sank in water, it was not possible to verify the integrity of the fuel on board nor was it possible to determine the exact amount of fuel on board at the time of the occurrence flight. Had automotive gasoline been mistakenly added to the aircraft main wing tanks and mixed with the aviation fuel already present in the wings, it would not have caused engine problems as many piston type aircraft operators using the same model of engine have a supplementary type certificate (STC) to use automobile type gasoline for their aircraft. The Aircraft Flight Manual recommends using 100LL, however the engine had been originally certified to fly with lower octane gasoline. The fuel valve selector was found in the ON position. Fuel filter bowl located on the engine pylon was found full of 100LL; the fact that fuel was present in the bowl would indicate that fuel was reaching the engine prior to impact with the water and engine stoppage.

Crashworthiness

It is estimated that impact forces with the surface of the water caused the nose section, including the instrument panel, control columns, rudder pedal areas and floor of the aircraft to tear away from the rest of the rear cabin area; consequently the 2 front seat attachment points failed. Both seats and floor tracks failed in overload. The applicable aircraft certification requirements at the time of manufacture of this Lake Buccaneer required that seats and their supporting structures be designed to sustain ultimate upward acceleration loads of 4.5 g,10 forward acceleration loads of 9.0 g and sideward acceleration loads of 1.5 g.11 The aircraft struck the water with both a forward and right sideward movement. When a seat does not remain securely attached to the floor, occupant injury protection offered either by the seat or by the safety belt and shoulder harness is considerably reduced.

The occurrence aircraft was equipped with safety belts and shoulder harnesses. The left portion of the pilot’s safety belt attachment point attached to the left side wall had failed in overload indicating that it was worn at the time of impact. It was not the pilot’s habit to wear the shoulder harness; the left side shoulder harness was found intact. The pilot was found in the aircraft. The passenger’s safety belt and shoulder harness were found intact and unfastened; this does not necessarily indicate that the passenger was not wearing the belt because it may have come unfastened during the crash sequence. The passenger was found 80 feet from the aircraft. His seat was not retrieved. One inflatable life vest was found in the wreckage. Neither occupant was found wearing a life vest, nor is it required.

The Emergency Locator Transmitter

The emergency locator transmitter (ELT) on board C-GGFK was a KANNAD 406 AF‑Compact ELT manufactured in France. It was programmed, installed and tested in April 2009. It was found in the ARM position when it was retrieved from the aircraft.

The TSB tested the ELT to verify its serviceability. The tests showed that the ELT still met the 121.5 MHz signal requirements. However it no longer met the 406 MHz signal requirements. The ELT would transmit an amplitude modulated sweeping audio signal on 121.5 MHz carrier frequency but would not transmit the data burst on a 406 MHz carrier frequency. The ELT‘s 15-digit hexadecimal identification is the data that is transmitted by the ELT on its 406 MHz carrier frequency. In addition it could no longer be armed or activated when impacted. The most probable cause for the ELT‘s failure to meet the 406 MHz signal and impact activation requirements is considered to be water and pressure damage by the immersion of the ELT to a depth of 230 feet.

At present, seaplanes only need to carry an ELT; no alternate means of emergency locating or tracking is required. Although seaplane occurrences can happen over land, many occur at low speeds during taxi maneuvres, landing and take-off on water. In these cases, the impact forces may not be strong enough or are not in the appropriate direction to activate the ELT inertia switch. In other cases, the ELT will become submerged partially or totally, rendering the unit unable to transmit its signal through water. If occupants are able to exit the aircraft, they find themselves unable to retrieve and activate the submerged ELT. If the aircraft becomes overdue and search is initiated, the aircraft and ELT may have sunk making it more difficult to locate. Survivability is dependent on rapid search and rescue, and medical response.

Recent technology offers an array of emergency signalling devices for water and land. Present regulation does not require seaplanes to carry a deployable, waterproof-type emergency position indicating radio beacon (EPIRB), even though many seaplane occurrences take place on water. Used on water-borne vessels, EPIRBs are similar to ELTs but are water-tight and are fixed to an area of the vessel where, in the event of capsizing, the EPIRB would float and emit a signal to initiate search and rescue efforts. Activation takes place on contact with the water. EPIRBs are used on commercial marine vessels but are not required for private pleasure craft. For aviation purposes there are ELTs that are standalone equipment capable of floating and intended to be removed from the aircraft. These ELTs are equipped with an auxiliary antenna and activated manually by survivors or automatically by a water switch sensor when in contact with water.

If occupants do egress from a seaplane, they are often injured and unable to reach the ELT. Many life preservers offer the personal locator beacon (PLB) option. Although present regulation requires that a life preserver be carried for each occupant of a seaplane, they do not have to be worn nor do they have to carry a PLB.12

In this case, the search for and recovery of the sunken aircraft and its occupants took close to a month and involved numerous resources. The expeditious location of underwater aircraft wreckage is essential for investigative purposes. An underwater location beacon (ULB), installed and operating, would likely have led to the wreckage being located more quickly. The ULB is designed to activate upon immersion and to transmit an acoustic signal at 37.5 kilohertz (kHz).13 This signal propagates well in water and is normally easily detected using portable hydrophone detection equipment.

Transport Canada has been reassessing its policy on ELT requirements since 2007.

Glassy Water

Lac Berté is a large body of water with various inlets, bays and islands. An outfitter operates on the lake and cottages are sparsely dispersed along its shoreline. However, because of the outfitter’s rights to the lake, no one, other than the outfitter’s clients, is allowed to fish there. The pilot knew the area well and likely would not have intentionally landed on Lac Berté unless there had been an emergency situation.

The pilot was experienced in landing on water; however glassy water conditions are considered to be the most difficult conditions for landing a seaplane regardless of experience. The mirror effect created under glassy water conditions affects depth perception. If glassy water conditions exist, the following is recommended:

Power assisted approaches and landings should be used although considerably more space will be required. The landing should be made as close to the shoreline as possible, and parallel to it, the height of the aircraft above the surface being judged from observation of the shoreline. Objects on the surface such as weeds and weed beds can be used for judging height. The recommended practice is to make an approach down to 200 feet (300 feet to 400 feet where visual aids for judgment of height are not available) and then place the aircraft in a slightly nose high attitude. Adjust power to maintain a minimum rate of descent, maintaining the recommended approach speed for the type until the aircraft is in contact with the surface. Do not “feel for the surface”. At the point of contact, the throttle should be eased off gently while maintaining back pressure on the control column to hold a nose high attitude which will prevent the floats from digging in as the aircraft settles into the water. Care must be taken to trim the aircraft properly to ensure that there is no slip or skid at the point of contact.14

In the case of the Lake type aircraft, which are known to be more challenging to land when engine power is off or at idle, it is recommended that some engine power be maintained in order to properly control the rate of descent. It is also recommended to keep a speed of 65 mph until touchdown. If the height above the surface is not judged appropriately on approach and touchdown, it is likely that the aircraft will either hit the water hard because the pilot will not have levelled off in time for the aircraft to touchdown smoothly on the surface, or the pilot may level off too high, believing the aircraft is lower than it actually is. This can result in the aircraft stalling high above the water as the pilot reduces speed and pulls the nose up to land. It is possible that one wing stalls before the other, making the aircraft bank to the right or left, causing one wing to collide with the water.

The aircraft was found approximately 1476 feet laterally from the closest landmark. This distance would not have allowed the pilot to effectively judge the height of the aircraft above the water under glassy water conditions. The examination of the vertical speed indicator also showed a rate of descent between 1000 to 1500 feet per minute which would require a certain height above the water to attain.

The Pilot’s Medical History

The 78-year-old pilot held a valid category 3 medical certificate. The pilot’s last aviation medical examination took place on 23 July 2009. In 1987, it was found that the pilot had previously had a heart attack. A thorough cardiac investigation to assess the suitability for pilot medical recertification was conducted. Also in 1987, the pilot was found to have diabetes mellitus (Type 2 diabetes). Present regulations require that private pilots, 40 years and older, complete an aviation medical examination every 2 years. Because the occurrence pilot was diagnosed with several medical conditions, heart disease, hypertension, and diabetes, Transport Canada required that there be an annual follow-up. The pilot’s family doctor was also aware of the pilot’s health issues. The pilot was expected to complete and forward to Transport Canada, the results of various required medical tests relative to the diabetes and heart conditions, on an annual basis in order to maintain the category 3 medical certificate required for the private pilot licence. The pilot’s next medical examination was due in July 2010.

The pilot had a fairly active lifestyle and anecdotal descriptions of the pilot’s health and demeanour indicated that the pilot was feeling well and was disciplined in taking medications as prescribed.

The Passenger

The 69-year-old passenger had a heart condition. The passenger had a heart attack in 1990 followed by bypass surgery in 2000 and was taking medication for the heart, hypertension and hypercholesterolemia. The passenger was reported to be feeling well and had not mentioned any recent health concerns. The passenger was not a licensed pilot.

Post-Mortem Examination

Given their medical histories, autopsies were performed on both the pilot and passenger to help determine if either of them had suffered a medical event that could have led to incapacitation in flight.15

The autopsies performed did not determine that either occupant had an incapacitating medical event in flight. Heart attacks or angina attacks do not always leave markers evident in a post-mortem examination.

Neither occupant died of injuries incurred during the crash sequence. Both were seriously injured and died of drowning. The pilot had fractures to the upper maxilla (jaw bone), and both wrists. Fractures to the pilot’s wrists (bracing maneuvre) would likely indicate that he was conscious and at the controls at the time of the impact with the water. The passenger also had fractures to the face and dislocation of the right ankle. There were no fractures to the passenger’s hands or arms. It is likely that the serious injuries to the facial area rendered the occupants unconscious. The post-crash environment, i.e. the water, would have played a key role in their inability to survive.

Toxicology results did not show the presence of illicit drugs or alcohol in either occupant. Test results did show the presence of the pilot’s prescribed medications for treatment of high cholesterol and high blood pressure, although quantities could not be determined. The absence of high levels of lactic acid and glucose in the vitreous humor (liquid in the eye), would indicate that the pilot did not have a fatal hyperglycaemic event. The passenger was prescribed nitro‑glycerine spray to relieve angina. Present analysis methods do not allow for valid testing for the presence of nitro-glycerine; therefore, it could not be determined if the passenger had used nitro-glycerine.

Review of Pilot’s Aviation Medical Information

An expert medical opinion and review of the pilot’s TC aviation medical records, family medical records and guidelines provided by the Handbook for Civil Aviation Medical Examiners was obtained. The following information was extracted from the medical expert’s report:

  • A review of the pilot’s TC medical file showed that the pilot had appropriate and timely evaluations and treatment by clinical providers with respect to his diabetes and heart disease, and appropriate medical oversight by his Canadian Aviation Medical Examiner (CAME), and the TC Regional Aviation Medical Officers (RAMO). TC oversight was in accordance with the published guidelines for cardiovascular disease and diabetes.
  • The guidance provided with respect to assessment and follow-up of cardiovascular disease and diabetes mellitus are contained in the relevant chapters of the Handbook for Civil Aviation Medical Examiners.16 Both the guidelines have been updated in the past year and a half. The updated guidelines provide appropriate and current recommendations for assessment and follow-up relevant to this case.
  • The pilot’s diabetes was relatively mild and appeared to be controlled well and was very unlikely to contribute to performance impairment.
  • The pilot had regular eye specialist evaluations with no evidence of diabetic retinopathy. However the pilot did have a venous occlusion in the right eye (1992) which resulted in some loss of visual acuity, which remained no better than 6/9 in the eye. It is possible that this (rather small) degree of anisometropia17 could affect depth perception.
  • It is unlikely that the accident was caused by an acute incapacitation in the pilot. Brace fractures to both wrists indicate that the pilot was likely conscious at the time of impact. The findings following the autopsy do not rule out the possibility of more subtle degrees of impairment related to the pilot’s underlying medical conditions: diabetes, hypertension and heart disease.
  • Review of family doctor records show that the pilot had been appropriately treated and followed for each of his medical conditions. With the pilot’s history of past myocardial infarction, hypertension, diabetes and dyslipidemia, he was at increased risk for another cardiac event, but ongoing serial monitoring did not suggest this was imminent.

Safety Studies

In 1994 the TSB published a safety study of survivability in seaplane accidents.18The analysis covered a 15-year period, from 1976 to 1990. During that period, there were 1432 such accidents; of these accidents, 103 accidents terminated in water and resulted in 168 deaths. The study aimed to advance aviation safety by identifying factors affecting occupant survivability in seaplane accidents that terminate in the water. The causes of death for the 168 fatalities19 from accidents which occurred on the water fell into 4 major categories as follows:

  • 18 (11%) of the deaths occurred during impact;
  • 17 (10%) of the occupants were incapacitated during the impact sequence from non-fatal impact forces and subsequently drowned;
  • 113 (67%) died from drowning;
  • and 3 (2%) died from exposure.

Crashworthiness studies conducted in the United States and Canada have consistently concluded that the probability of surviving impact forces is significantly enhanced if occupants of small, general aviation aircraft are protected by upper-torso restraints.20 Occupants of a seaplane aircraft may drown in a sinking aircraft if they are unconscious; loss of consciousness is normally caused by a head trauma. If restrained and protected during the impact sequence, occupants may maintain consciousness and stand a better chance of successfully exiting a sinking aircraft. The use of a 3-point safety restraint (safety belt and shoulder harness) is known to reduce the severity of upper body and head injuries and more evenly distribute impact forces.21

Very little data regarding the availability of shoulder harnesses were available during the TSB 1994 seaplane study. However where information was recorded, 60% of the passengers did not have shoulder restraint available; of the remaining 40%, over half did not make use of the available shoulder restraint systems. Information concerning the use of shoulder restraints by pilots was more complete. Sixty two percent (62%) of pilots were operating aircraft that had not been equipped with shoulder harnesses. Of the pilots that did have shoulder harnesses available, 68% were not using them at the time of the accident. Aircraft built before 1978 were not required to have shoulder harnesses available.22 Many of these aircraft are still operational today. Aircraft manufactured after July 18, 1978 require the installation of shoulder harnesses for each front seat and their use during taxi, take-off and landing, and in flight if necessary for safety.23

Although regulation states that restraints must be used for movement on the ground (water), take-off and landing, or whenever it is deemed necessary for the safety of the occupants, it is not mandatory to wear the restraints for other than these specified phases of flight. It is likely that in the event of an emergency, restraints not worn in flight may be forgotten and not used during the emergency sequence and impact.24 In this occurrence, it is not known if the passenger received a safety briefing, including the use of restraints and egress, prior to flight nor could it be determined if the safety belt and shoulder harness available had been used.

Safety Information and Statistics

The number of occurrences and fatalities in Canada over the past 20 years for both commercial and private operations has remained relatively the same for each of these operation types (Table 1). In an effort to increase seaplane safety, TC has recently published and distributed seaplane safety literature, Seaplanes – A Passenger’s Guide,25 throughout the aviation community.

Many occurrences involving floatplanes and seaplanes have been investigated by the TSB. Many of these occurrences have led to safety studies and safety communications in the effort to improve floatplane and seaplane safety. Such efforts have addressed piloting skills, abilities and knowledge of seaplane pilots including landing on glassy water and rough water, survivability in seaplane accidents, passenger briefing and safety features, fitting of emergency exits for rapid egress, donning of personal floatation devices. A list of these efforts was recently published as an appendix to the TSB aviation investigation report into the floatplane occurrence, A09P0397 Loss of Control – Collision with Water.

Floatplane Statistics (includes seaplanes)
Table 1. Table 1. Floatplane Statistics (includes seaplanes) ↑

The following TSB Laboratory reports were completed:

LP 092/2010 Photo Analysis
LP 093/2010 Instrumentation & Document Analysis
LP 099/2010 Engine Examination
LP 046/2011 Conversion ROV footage

Analysis

The reason for departing Lac de la Marmotte II on the evening of 03 June 2010 is unknown. It is possible the pilot decided to depart late in the day, although it was not his habit to do so, because of approaching weather due in the area the following day.

Two possible scenarios resulting in the collision with water were considered: a missed precautionary or emergency landing due to aircraft operation difficulties and glassy water conditions, or a loss of control of the aircraft due to pilot or passenger impairment. Risk factors that may have increased the likelihood of sudden impairment were considered for both the pilot and the passenger; both were at risk of a sudden medical event.

The first possible scenario is that the aircraft had some system malfunction that was not determined during the post-accident examination. However, this scenario would not explain why the pilot, with much experience landing on water, and with ample space on Lac Berté to make a precautionary landing, was not able to land the aircraft safely on the water. The pilot’s experience and skill level should have been sufficient to handle such an event. The last photo found in the passenger’s camera shows the aircraft at 876 feet above the water, giving ample altitude to maneuvre following a technical problem. Winds were light to nil and would not have affected the direction of the landing or aircraft performance as would strong winds.

Given that the lake surface conditions were glassy, the pilot would likely have chosen to land closer to a shoreline or island in order to help judge the height above the water. The aircraft was found 1476 feet from any shoreline, which indicates that the pilot likely did not actively choose the area in which it struck the water, either because the pilot was unable to do so or the situation did not allow time to do so.

The second scenario is a sudden medical event resulting in pilot or passenger impairment while in flight over Lac Berté. The passenger took pictures during take-off, climb and cruise suggesting there was no apparent imminent danger or worry at that point during the flight.

Both the pilot and the passenger had pre-existing health risk factors making it possible that either one of them may have experienced a medical event resulting in some degree of impairment possibly leading to distraction and/or a loss of control of the aircraft. Fractures to the pilot’s wrists would indicate that he was conscious and at the controls at the time of impact with the water. The pilot was monitored by his family doctor when necessary and by Transport Canada on an annual basis due to these increased health risk factors. Transport Canada assessed the pilot as fit. However, a medical event resulting in some level of impairment cannot be ruled out given the pilot’s age and health risk factors. The rate of descent of 1000 to 1500 feet per minute shown on the vertical speed indicator would be considered high for a planned attempt at landing the aircraft in glassy water conditions and would therefore possibly indicate that for some unknown reason, the pilot may not have been able to control the aircraft fully.

Had the pilot experienced a sudden medical event in flight, the passenger, a non-pilot, would not have known how to land the aircraft safely on water and most likely would not have known how to maintain straight and level flight and radio call for help.

The passenger did not have any fractures to the wrists or arms. This would likely indicate that he was not at the controls at the time of impact with the water. Had the passenger experienced a sudden medical event in flight, the pilot’s ability to control the aircraft may have been hindered.

The investigation could not determine if either the pilot or the passenger experienced an incapacitating medical event.

There was insufficient factual information to conclusively state why the aircraft descended and impacted the water.

Both occupants had severe facial injuries  which would usually indicate that they were not wearing shoulder harnesses. However, as the seats were torn from the floor attachments and could no longer restrain the occupants, it was not possible to determine if shoulder harnesses would have been effective. The nose section was torn open from right to left. The cabin seats were consequently torn from their attachment points, no longer restraining the occupants in place. Impact forces were likely above the design limits. Seat support and attachment failures can subject occupants to unfavourable positions that greatly reduce tolerance to injury. The severity of the facial injuries would require a substantial impact. It is likely that the occupants were rendered unconscious and were therefore unable to exit the aircraft before it sank. Lack of consciousness in a post-crash water environment contributed to their deaths by drowning.

Studies have indicated that in the majority of small general aircraft accidents, the shoulder harnesses are not worn. Shoulder harnesses reduce the risk of serious injury to the head and upper torso. Most deaths in seaplane occurrences are caused by drowning, either because the occupants cannot exit the aircraft and drown or the severity of their injuries renders them unable to exit.

Given the alerting limitations of ELTs if submerged in water, alternate sources of alerting and tracking an aircraft are required. TC has not yet completed its review and updating of ELT regulatory requirements.

Findings as to Causes and Contributing Factors

  1. It could not be determined why the aircraft descended and struck the surface of the water.
  2. The pilot and passenger seats failed when the aircraft floor was torn open on impact. The lack of effective occupant restraint during the impact sequence likely contributed to the severity of their injuries, rendering them unconscious and unable to survive the post-crash water environment.

Findings as to Risk

  1. Once an ELT is submerged, a signal cannot be transmitted through water, delaying initiation of rescue efforts.
  2. Not wearing shoulder harnesses increases the risk of serious injury to the head and upper torso in the event of an accident, which in turn may prevent a safe exit from the aircraft.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 03 July 2012.

Appendix A — Area Map of Lac Berté and Location of Aircraft

Area Map of Lac Berté and Location of Aircraft

Appendix B — Last photo taken with passenger’s camera and its location relative to direction of flight

Last photo taken with passenger's camera and its location relative to direction of flight

Last photo taken with passenger's camera
Photo 2. Last photo taken with passenger’s camera


  1. All times Eastern Daylight Time (Coordinated Universal Time minus 4 hours). ↑
  2. The lake on which the pilot’s cabin is located carries no official name. The pilot held a land lease lot #142540812, since 1991. Locally the lake is known as Lac de la Marmotte II and will be referred to as such in this report. ↑
  3. The occurrence took place in Class G airspace which is all uncontrolled domestic airspace where no air traffic control services are provided. Flight information and alerting services are, however, provided. The pilot filed a flight itinerary with a responsible person who initiated search and rescue efforts. ↑
  4. Canadian Aviation Regulations CAR 401.05(1)(a), Standard 421.05 and CAR 401.05(2). ↑
  5. Engine Lycoming model IO-360-A1B6, serial number L-23075-51A. ↑
  6. Propeller Hartzell model HC-E2YR-1BLF, serial number DK2071B. ↑
  7. EDO-AIRE, part number 1U262-001-9, serial number A10955E. ↑
  8. Aviation Instrument Mfg. Corp., part number 507-0020-901, serial number 1450. ↑
  9. Capacity of 54 US gallons or 45 Imperial gallons.
  10. 4.5 times the normal load of acceleration due to gravity at the Earth’s surface where 1 g is 9.80665 metres per second squared.
  11. Civil Air Regulations (amendment May 15, 1956), Part 3-Airplane Airworthiness; Normal, Utility, and Acrobatic Categories, Section 3.386 Protection & 3.390 Seats and Berths.
  12. CAR 602.62
  13. Canadian Coast Guard (CCG) helicopters were equipped with ULBs following the TSB investigation A00A0076 and safety information letter to Transport Canada into the Department of Transport Aircraft Services. Also, the personal floatation devices on board CCG helicopters are now equipped with PLBs.
  14. Transport Canada Aeronautical Information Manual (TC AIM), Airmanship, 2.11.4 – Landing Seaplanes on Glassy Water.”
  15. The definition of incapacitation is to deprive of power, strength, or capacity; disable. Collins English Dictionary – Complete and Unabridged. Harper Collins 2003
  16. Transport Canada publication TP13312
  17. Where there is an inequality in refractive power of the two eyes
  18. The word ˝seaplane˝ is used by Transport Canada for licensing purposes and includes floatplanes, flying boats and amphibious aeroplanes.
  19. In 17 cases (10%), no cause of death was recorded.
  20. Small Aircraft Crashworthiness, Volume 1 TP 8655E, Prepared by Sypher: Mueller International Inc., July 1987, page 46. Study of the Influence of Shoulder Harnesses in Aviation Safety, Canadian Aviation Safety Board, 1987.
  21. National Transportation Safety Board, Safety Report, NTSB/SR-83/01, General Aviation Crashworthiness Project, Phase Two – Impact severity and potential injury prevention in General Aviation accidents, March 15, 1985.
  22. CAR 605.24(1)
  23. CARs 605.24(1) and 605.25(1)
  24. A survivable accident is one in which the forces transmitted to the occupant through the seat and restraint system do not exceed the limits of human tolerance to abrupt accelerations and in which the structure in the occupant’s immediate environment remains substantially intact to the extent that a livable volume is provided throughout the crash sequence. National Transportation Safety Board, Safety Report, NTSB/SR-83/01, General Aviation Crashworthiness Project, Phase One, June 27, 1983, page 3.
  25. TP12365

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Aviation Reports – 2011 – A11C0102

| Transportation Safety Board Reports | June 21, 2012

Transportation Safety Board of Canada

Aviation Reports – 2011 - A11C0102

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Runway Overrun
Beaver Air Services Limited Partnership
(Missinippi Airways)
Cessna 208B, C-FMCB
Pukatawagan, Manitoba
04 July 2011

Report Number A11C0102

Synopsis

The Beaver Air Services Limited Partnership Cessna 208B (registration C-FMCB serial number 208B1114), operated by its general partner Missinippi Management Ltd (Missinippi Airways), was departing Pukatawagan, Manitoba, for The Pas/Grace Lake Airport, Manitoba. At approximately 1610 Central Daylight Time, the pilot began the takeoff roll from Runway 33. The aircraft did not become fully airborne, and the pilot rejected the takeoff. The pilot applied reverse propeller thrust and braking, but the aircraft departed the end of the runway and continued down an embankment into a ravine. A post-crash fire ensued. One of the passengers was fatally injured; the pilot and the 7 other passengers egressed from the aircraft with minor injuries. The aircraft was destroyed. The emergency locator transmitter did not activate.

Factual Information

History of Flight

The aircraft was on the return leg of a daily scheduled flight from The Pas/Grace Lake, Manitoba Airport (CJR3) to the Pukatawagan Airport (CZFG). The flight, which departed at 1500, 1 from CJR3 to CZFG was uneventful. Shortly after arrival, the passengers deplaned. The passengers destined for CJR3 then boarded the aircraft for the return flight.

Pukatawagan Aerodrome diagram
Figure 1. Pukatawagan Aerodrome diagram
(Source: NAV CANADA, Canada Air Pilot,
Effective 10 April to 29 July, 2011) ↑

The pilot entered the aircraft and provided the passengers with a short safety briefing. During the briefing, some passengers were engaged in other activities such as stowing their personal belongings and fastening their seat belts. After entering the cockpit, the pilot started the engine, completed the pre-takeoff checks, broadcast a traffic advisory, and backtracked for departure on Runway 33. The aircraft turned in the turning bay and the pilot advanced power for a rolling takeoff from the beginning of the runway.

During the takeoff run, the aircraft’s airspeed indicator initially rose as the aircraft accelerated and its nose wheel lifted off the runway. The flaps were set to 20° and the engine produced rated power. During the takeoff roll, the aircraft encountered several soft spots near the taxiway intersection (Figure 1). The pilot applied rearward pressure on the control yoke and one or both main wheels briefly lifted off the runway, but the airspeed stopped increasing and the aircraft did not remain airborne. The pilot rejected the takeoff with an estimated 600 feet of runway remaining. The pilot selected engine power to idle, reverse propeller thrust, and flaps to 0° to maximize braking traction. The aircraft continued past the end of Runway 33. The aircraft was travelling at a relatively low speed but the pilot was unable to stop before the aircraft dropped off the steep slope and proceeded down an embankment before coming to rest in a ravine (Photo 1). The aircraft encountered rocks and a sharp slope reversal at the bottom of the ravine. Several of the occupants were injured by the sudden stop. As a result of the impact, the aircraft was damaged and its fuel system was compromised. A post-crash fire ensued almost immediately and consumed most of the aircraft. One of the passengers injured in the accident died because of smoke inhalation due to the post-crash fire.

Accident site, looking back at the end of Runway 33 (Pukatawagan Airport)

Photo 1. Accident site, looking back at the end of Runway 33 (Pukatawagan Airport)↑

Evacuation

Passengers seated toward the rear of the aircraft had difficulty opening the aircraft’s rear cabin exit door. After several attempts by different passengers, they were successful and were able to escape the wreckage. The front right seat passenger assisted the pilot, who was initially trapped in the seat. That passenger also assisted the front left seat passenger who was injured to the head during the impact and was unconscious. The pilot and front right seat passenger then attempted to extricate the unconscious front left seat passenger, but the fire progressed rapidly and the resulting heat and smoke forced them to discontinue and leave the burning aircraft. The aircraft’s passenger seating arrangement and exit locations are depicted in Appendix A. The surviving occupants made their way up the embankment and then to the airport terminal building. Airport workers arrived in vehicles and assisted some of the surviving occupants. The survivors were taken to the nursing station for medical attention, and later evacuated by aircraft to The Pas/Grace Lake. The Pukatawagan Fire Department attended the site and the fire was extinguished at approximately 1645.

Pilot Information

The pilot was certified and qualified for the flight in accordance with existing regulations. He had been employed by Missinippi Airways since March 2010, and had accumulated about 1900 total flight hours, with about 400 flight hours on the Cessna 208B aircraft type. The captain’s flight and duty time limits were not exceeded. There was no indication that the pilot was fatigued.

A review of the training records indicated that the pilot’s training complied with the requirements of the approved company training manual. This training included, in part, flight and duty time requirements, aircraft instrument and equipment requirements, weather, surface contamination, passenger and cabin safety, and emergency procedures.

The pilot had been into CZFG on numerous occasions in the past. This was the occurrence pilot’s third flight into CZFG on the day of the occurrence. The previous flights that day had been conducted using a different aircraft type.

Aircraft Information

The Cessna 208B is a high-wing, fixed gear aircraft equipped with a Pratt & Whitney Canada PT6A-114A turboprop engine. The accident aircraft was manufactured in 2005 and was equipped with a cargo pod, and had been modified with a Transport Canada approved kit to increase the maximum allowable takeoff weight to 9062 pounds. The aircraft had about 900 pounds of fuel on board at takeoff, and the payload consisted of 8 passengers and their baggage. Damage to the aircraft precluded weighing of the aircraft load after the accident. However, the investigation determined that the aircraft’s gross weight was approximately 8050 pounds on departure and that the centre of gravity was within allowable limits.

The normal liftoff speed of the C208B is 70 knots. Performance information in the aircraft’s Pilot Operating Handbook (POH) indicated that the takeoff distance, ground roll, at the prevailing temperature2 and elevation should have been about 1300 feet on a paved, level, dry runway using the short field takeoff technique. According to the POH, the landing distance, ground roll, under the same conditions is about 1000 feet.

The Cessna 208B short field takeoff technique from the POH is as follows:

Wing flaps – 20°
Brakes – apply
Power – set for takeoff
Annunciators – check
Brakes – release
Rotate – 70 knots
Climb speed – 83 knots

The amplified POH short field technique suggests to use 20° flap, raise the nose when practical and climb out with the tail low and then level the airplane to accelerate to a safe climb speed.

The Cessna 208B POH does not list a rejected takeoff procedure, but the emergency procedure for engine failure before takeoff specifies:

Power lever – Beta range
Brakes – Apply
Wing flaps – Retract

The performance changes resulting from the runway conditions prevailing at Pukatawagan at the time of occurrence could not be accurately quantified. The Cessna 208B type is certified without published accelerate-stop or accelerate-go distance calculations. However, test data provided by the aircraft manufacturer for takeoff distances with 20° flap at 73 KTAS indicated that a takeoff run on a hard gravel surface would be about 11% longer than that on a paved dry runway. A landing roll would be about 18% longer on a gravel runway. The manufacturer’s data, with gravel correction factors, is summarized in Appendix B. According to the aircraft manufacturer, if the POH technique is used as described, under the prevailing conditions and on a hard gravel runway, the aircraft’s accelerate-stop distance should have been 2259 feet with flaps 20° set for takeoff and then flaps full during the rejected takeoff. No information was available in the POH for takeoff with flaps 20° and a rejected takeoff with flaps 0°.

Records indicate that the aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The cockpit-mounted engine power lever allows the pilot to control engine power. It is connected through a linkage to a cam assembly mounted in front of the fuel control unit at the rear of the engine. The bolt attaching the linkage to the power control lever arm assembly was sent to the TSB Laboratory for examination. The attachment bolt’s dimensions were taken and the results were found to be consistent with an AN3-14 bolt instead of the specified AN3-16 bolt. An AN3-14 bolt is 0.25 inch shorter than the AN3-16 bolt. There was a spacer (P/N NAS43HT-46) missing from the bolt. The dimension of the spacer is 46/64 inch (0.719 inch) long, and it would not have been possible to install the specified spacer in the occurrence power control assembly on the AN3-14 bolt, as it was too short. Some metal splatter on the adjacent fuel flow transmitter indicated that it was likely that some kind of aluminum spacer, possibly an aluminum washer, had been installed between the two cadmium-plated steel washers found on the lever arm, before the occurrence. This aluminum washer probably melted during the post-crash fire and the molten aluminum dripped and solidified onto the fuel flow transmitter. There was no indication that the power lever arm anomalies affected the operation of the engine or its power control.

Short and Soft Field Takeoffs

The objective of short field takeoff technique is to effect a takeoff from a firm surface in the shortest possible distance. Commonly-accepted techniques include:

  • Apply full power before brake release;
  • Put controls on neutral during the takeoff run to minimize aerodynamic drag; and
  • Rotate as soon as the aircraft is able to fly and accelerate to climb speed in ground effect.

The objective of soft field technique is to effect a takeoff in soft or rough conditions while minimizing damage. Commonly-accepted techniques include:

  • Rolling takeoff to minimize propeller damage;
  • Using of elevator early to lift the nose wheel and lighten the load on the main wheels with aerodynamic lift;
  • Maintaining nose-high attitude until aircraft lifts off the ground;
  • Using increased aerodynamic drag inherent in this technique is accepted where takeoff distance permits, in order to achieve liftoff in soft conditions with minimum damage.

Many of the airports from which the company operates have gravel-surfaced runways. The company used the terms soft field and short field takeoff interchangeably. The company considered Pukatawagan to be a short field runway and taught company pilots to use the takeoff technique as described below. Company pilots using this technique did not report performance problems. The procedure taught by the company for these takeoffs consists of:

  • Rolling takeoff with gradual application of power
  • Using elevator to lighten the weight on the nose wheel
  • Lifting the nose wheel off the runway, once airspeed allows
  • Rotating and climbing out, at normal departure airspeed

When the nose wheel is lifted from the runway, the aircraft’s induced aerodynamic drag would increase during the takeoff roll. The amount of increased drag and resulting increased takeoff distance is not quantified and depends on the degree of rotation and individual pilot technique.

Meteorological Information

There are no routine weather observations available for the Pukatawagan Airport. While the aircraft was being taxied for departure, the windsock indicated a surface wind of about 10 knots, generally westerly and favouring Runway 33, but varying up to 90° in direction.

A special weather observation (SPECI) issued at 1625 for Lynn Lake, Manitoba, 67 nautical miles (nm) north of Pukatawagan, was as follows: wind 230° true (T) at 5 knots, wind direction varying from 220°T to 290°T, visibility 9 statute miles (sm), scattered cloud based at 7600 feet above ground level (agl), broken cloud ceiling based at 9300 feet agl, temperature 16°C, dew point 13°C, with distant lightning observed to the southeast.

The observed weather at 1600 for Flin Flon, Manitoba, 65 nm southwest of Pukatawagan, was as follows: wind 280°T at 12 knots gusting to 22 knots, visibility 15 sm, scattered cloud based at 5500 feet agl, temperature 25°C, dew point 8°C. The investigation determined that the weather conditions at Pukatawagan at the time of the occurrence were similar to those at Flin Flon.

The area forecast indicated that the area was under the influence of an upper low pressure system over northern Saskatchewan, supporting a surface low pressure system centered just north of Stony Rapids, Saskatchewan. A meteorological assessment carried out by Environment Canada concluded that a moderate westerly pressure gradient and convectively unstable environment across northwestern Manitoba resulted in moderate westerly surface winds with gusts in the 18-22 knot range throughout the afternoon on 04 July 2011. In addition, it had been raining considerably at the Pukatawagan Airport in the last 2 days before the occurrence. Satellite imagery around the time of the incident shows evidence of an outflow boundary from a thunderstorm cell to the north of Pukatawagan moving through the aerodrome in the 1600 to 1630 time frame. This outflow boundary had the potential to produce an abrupt onset of northwesterly wind gusts as strong as 40 knots and the possibility of wind shear. The possibility of a dry microburst associated with the weaker convective cloud that was observed moving along the outflow boundary was also considered. In the event of a dry microburst near the aerodrome, it has been approximated that brief surface wind gusts on the order of 60 knots was a possibility. It is important to point out that while the potential had been identified, the probability of a significant dry microburst was considered low and there is no indication that a dry microburst occurred.

Aerodrome Information

The Pukatawagan Airport is owned and operated by the Province of Manitoba, Department of Infrastructure and Transportation. It has a single runway (Runway 15/33) that is 3000 feet (approx. 914 m) long by 85 feet (approx. 26m) wide. A turnaround area is located at each end of the runway. The turnaround area at the end of Runway 33 is 230 feet (approx. 71 m) long. The gravel-surfaced runway was wet at the time of the occurrence, and several ruts from other aircraft tires were visible on the surface of the runway.

Beyond the turnaround area, the prepared surface gives way to an embankment which descends into a ravine. The slope of the embankment is approximately 30° to 45° and is comprised of gravel, rocks, and large boulders. The slope descends about 20 feet vertically, and then reverses sharply into the contour of a ravine.

Transport Canada publication TP 312E entitled Aerodrome Standards and Recommended Practices (TP 312E) requires that a runway and any associated stopway shall be included in a runway strip. According to TP 312E, a strip shall extend before the threshold and beyond the end of the runway or stopway for a distance of at least 60 m where the code number is 2, 3 or 4. The code is intended to provide a method for linking the characteristics of aerodromes with the aeroplanes that are intended to operate there. The code is composed of 2 elements which are related to the aeroplane performance characteristics and dimensions. Element 1 is a number based on the aeroplane reference field length and element 2 is a letter based on the aeroplane wing span and outer main gear wheel base. The Cessna 208B aircraft has a wingspan of 16 m and a main gear wheel span of 3.6 m.

TP 312E references for airport codes 2(b), 3(c), 4(d), and 4(e) are as follows

Code number Aerodrome Field Length Code letter
2 800 m up to 1200 m (b)
3 1200 m to 1800 m (c)
4 1800 m and over (d)
4 1800 m and over (e)

The airport code for the Pukatawagan Airport is 2 (b).

TP 312E also recommends runway end safety areas (RESAs) for some airports:

A runway end safety area should be provided at each end of a runway strip where the code number is 3 or 4. The runway end safety area should extend from the end of a runway strip for as great a distance as practicable, but at least 90 m. A runway end safety area should provide a cleared and graded area for aeroplanes which the runway is intended to serve in the event of an aeroplane undershooting or overrunning the runway. The surface of the ground in the runway end safety area does not need to be prepared to the same quality as the runway strip. The longitudinal slopes of a runway end safety area should not exceed a downward slope of 5 per cent. Longitudinal slope changes should be as gradual as practicable and abrupt changes or sudden reversals of slopes avoided. The transverse slopes of a runway end safety area should not exceed an upward or downward slope of 5 per cent. Transitions between differing slopes should be as gradual as practicable. A runway end safety area should be so prepared or constructed as to reduce the risk of damage to an aeroplane undershooting or overrunning the runway and facilitate the movement of rescue and fire fighting vehicles.

The Pukatawagan Airport meets the stopway requirement of TP 312 for its currently assigned airport code. However, the Pukatawagan Airport, as well as many other airports with similar sized runways, is often used by much larger aircraft than a Cessna 208B. One example is the Hawker Siddeley HS-748 aircraft type, with a wingspan of 30 m. and a main gear wheel span of 7.6 m. Some other aircraft types including the Cessna 550, Lockheed L188, de Havilland DHC-8 and Douglas DC4 have also operated from Pukatawagan and other airports across northern Ontario and Manitoba. Regardless of the airport code, a RESA would reduce risk to aircraft using the Pukatawagan airport. Although the runway at Pukatawagan was compliant with TP 312E, the topography of the terrain beyond the runway end contributed to aircraft damage and to the injuries to crew and passengers. Harsh runway-end conditions prevail at several other airports in northern Manitoba, in Ontario, and in other areas. For example, both runway ends at St. Theresa Point, Manitoba, descend steeply to a lake. Steep drop-offs are also found at the ends of runway 26 at Kenora, Ontario, runway 27 at Pickle Lake, Ontario, runway 31 at North Spirit Lake, Ontario and runway 18 at Flin Flon, Manitoba.

During the last 10 years, there have been a number of occurrences in which aircraft overran runways in Canada (Appendix C). The occurrences indicate that shorter runway overruns into benign conditions often resulted in few injuries and little or no property damage. Longer overruns into harsh conditions such as the one in Pukatawagan resulted in death or injury, and more property damage. The TSB has identified runway overruns as an issue on its Watchlist, which notes that:

The TSB has investigated a number of landing accidents and incidents and has identified deficiencies, made findings, and issued safety communications such as runway surface condition reporting requirements and recommendations on runway end safety areas (RESAs). Specifically, in the past 10 years, the TSB has issued 1 recommendation and 4 safety communications on this issue, but more must be done to ensure safe landings. In bad weather, pilots need to receive timely information about runway surface conditions. Airports need to lengthen the safety areas at the end of runways or install other engineered systems and structures to safely stop planes that overrun.

The overrun area for Runway 33 is also the terrain underlying the final approach for Runway 15. An aircraft undershooting an approach for Runway 15 would be faced with the steep slope and rocky ground encountered by the aircraft in this occurrence, but at higher speed and with greater impact forces, leading to a high likelihood of passenger injury and damage to aircraft.

Flight Recorders

There is no regulatory requirement for this type of aircraft to carry any recorders; however, it was equipped with an event recorder designed to record and store certain engine performance parameters for maintenance purposes. This recorder was heavily damaged in the post-crash fire and none of its stored information could be retrieved.

Wreckage and Impact Information

The aircraft was destroyed by impact forces and fire, and examination of the wreckage was limited as a result. However, control continuity was established and one of the main landing gear tires revealed flat-spotting, indicating heavy braking. The flap system was found in the 0° position. Damage to the propeller was considered to have resulted from impact forces and fire. No pre-existing malfunctions or defects were found.

Medical and Pathological Information

The front left seat passenger, seated directly behind the pilot and the bulkhead separating the cabin from the cockpit , was wearing a seatbelt, but was not wearing the available shoulder harness. That passenger was severely injured to the head due to the impact and subsequently died of smoke inhalation.

Fire

Impact forces caused deformation of the aircraft structure which compromised the fuel system. Fuel was released at the rear of the engine, in the vicinity of the aircraft’s battery and exhaust system. Both of these items had the capacity to ignite the fuel and a fire resulted almost immediately. The fire was fed by fuel which flowed by gravity from the fuel tanks in the wings. The nose-down attitude of the aircraft in the ravine placed the fire below the aircraft’s cabin and the heat and flames therefore moved into the cabin within a short time, limiting the survivable time inside the cabin after the accident.

Previous TSB Recommendations

Post-impact fires have been documented as a risk to aviation safety in previous TSB investigations. As well, following TSB Safety Study SII A05-11 completed in 2006, the TSB concluded that requirements to consider and adapt countermeasures in new aeroplane designs may significantly reduce the risk and incidence of post-impact fires in impact-survivable accidents. Therefore, the Board recommended that:

To reduce the number of post-impact fires in impact-survivable accidents involving new production aeroplanes weighing less than 5700 kg, Transport Canada, the Federal Aviation Administration, and other foreign regulators include in new aeroplane type design standards: methods to reduce the risk of hot items becoming ignition sources; technology designed to inert the battery and electrical systems at impact to eliminate high-temperature electrical arcing as a potential ignition source; requirements for protective or sacrificial insulating materials in locations that are vulnerable to friction heating and sparking during accidents to eliminate friction sparking as a potential ignition source; requirements for fuel system crashworthiness; requirements for fuel tanks to be located as far as possible from the occupied areas of the aircraft and for fuel lines to be routed outside the occupied areas of the aircraft to increase the distance between the occupants and the fuel; and improved standards for exits, restraint systems, and seats to enhance survivability and opportunities for occupant escape. (A06-09, issued 29 August 2006)

Transport Canada (TC) responded to this recommendation in November 2006 and January 2007, but because these responses contain no action or proposed action that will reduce or eliminate the risks associated with this deficiency, the overall response to Recommendation A06-09 was assessed as Unsatisfactory. The Board has determined that as the residual risk associated with the deficiency identified in Recommendation A06-09 is substantial and no further action is planned by TC, continued reassessments will not likely yield further results.

The Board also found that there are a large number of small aircraft already in service and the defences against post-impact fires in impact-survivable accidents involving these aircraft are and will remain inadequate unless countermeasures are introduced to reduce the risk. The most effective ways to prevent post-impact fires in accidents involving existing small aircraft are to eliminate potential ignition sources, such as hot items, high-temperature electrical arcing and friction sparking, and prevent fuel spillage by preserving fuel system integrity in survivable crash conditions. Technology that is known to reduce the incidence of post-impact fires by preventing ignition and containing fuel in crash conditions may be selectively retrofitted to existing small aircraft, including helicopters certified before 1994. Therefore, the Board recommended that:

To reduce the number of post-impact fires in impact-survivable accidents involving existing production aircraft weighing less than 5700 kg, Transport Canada, the Federal Aviation Administration, and other foreign regulators conduct risk assessments to determine the feasibility of retrofitting aircraft with the following:

  • selected technology to eliminate hot items as a potential ignition source;
  • technology designed to inert the battery and electrical systems at impact to eliminate high-temperature electrical arcing as a potential ignition source;
  • protective or sacrificial insulating materials in locations that are vulnerable to friction heating and sparking during accidents to eliminate friction sparking as a potential ignition source; and
  • selected fuel system crashworthiness components that retain fuel.

(A06-10, issued 29 August 2006)

TC responded to these recommendations in November 2006 and January 2007, but because these responses contained no action or proposed action that would reduce or eliminate the risks associated with this deficiency, TC‘s overall response to Recommendation A06-10 was assessed as Unsatisfactory. The Board has determined that as the residual risk associated with the deficiency identified in Recommendation A06-10 is substantial and that no further action is planned by TC, continued reassessments will not likely yield further results.

The following TSB Laboratory report was completed:

LP 113/2011 – Analysis of Power Lever Hardware

This report is available from the TSB upon request.

Analysis

There was no indication that an aircraft system malfunction contributed to this occurrence. As a result, the analysis will focus on airport runway conditions, pilot technique and the decision to reject the takeoff, and the potential impact that environmental factors played in this occurrence. In addition, risks associated with overruns and passenger survivability will be analyzed with the objective of improving aviation safety.

The runway conditions at the Pukatawagan Airport had been adversely affected by recent rains. The rain caused some soft spots to form on the gravel-surfaced runway, most notably in the area near the taxiway intersection. However, these conditions would also have been present during the pilot’s previous operations at the airport on the day of the accident, albeit with a different aircraft type. No problems were noted during the pilot’s previous flights into CZFG, and no problems were reported by other aircraft operating in and out of CZFG on the day of the occurrence. The wet, soft gravel-surfaced runway condition impeded the aircraft’s ability to reach its required liftoff airspeed.

The pilot used the takeoff technique taught by the company. The technique used increased drag during the takeoff roll; however, the effect could not be quantified. The fact that the procedure had been in use for some time by the company suggests that performance decrements were likely small and could not be considered determinative. However, in this occurrence, one or both of the main landing gear wheels lifted off the ground momentarily but the aircraft was unable to fly away. This indicates that either the aircraft was rotated too early or a significant degree of rotation occurred before liftoff speed was attained. Either way, a significant amount of additional drag was incurred during the takeoff roll.

Weather analysis indicated that scattered to broken cloud with gusty winds predominated the area, with moderate gusty winds and occasional unstable convective activity with the possibility of wind shear. The weather conditions at the Pukatawagan Airport were not recorded, and there were no reliable indicators except the windsock.

The aircraft’s airspeed stopped increasing during the takeoff roll. This could have been caused by extra dragging, the soft runway or an unexpected wind shift or wind shear which would have been detrimental to takeoff performance. It is unknown whether those conditions would have affected the entire takeoff roll, had it not been rejected or whether they would have precluded a successful takeoff, had it been continued. Airmanship dictates that a pilot decides whether to abandon a takeoff  while there is still room to stop on the remaining runway. The lack of accelerate stop distance information for the aircraft impedes the crew’s ability to plan the takeoff-reject point accurately. Although the pilot’s decision to reject the takeoff was reasonable, the decision to reject was made at a point from which insufficient runway and turnaround area remained to bring the aircraft to a stop, resulting in the aircraft’s departure from the prepared surface.

The aircraft’s potential accelerate-stop distance under the prevailing conditions was within the length of the runway under ideal gravel runway conditions using a short field take off technique. The effects of the soft runway, gusty or shifting winds, and the technique used decreased the aircraft’s performance so that it consumed a significant portion of the runway length. The decision to reject with less than the required stopping distance remaining made a successful rejected takeoff impossible.

The airport runway had been used successfully for Cessna 208 and other aircraft operations for some time. However, during the runway overrun, the steep 20-foot drop-off and sharp slope reversal contributed to the impact damage that led to the deceased passenger’s injuries and the fuel system damage that in turn caused the fire. The aircraft’s orientation at the bottom of the slope exacerbated the heat effect and the speed at which the fire spread. The hostile terrain at the end of Runway 33 contributed to the occupants’ injuries and fuel system damage that in turn caused the fire. This complicated the passenger evacuation and prevented the rescue of the injured passenger.

Harsh runway-end conditions prevail at several airports across northern Manitoba, Ontario, and other areas. Although the runway at Pukatawagan was compliant with TP 312E, the topography of the terrain beyond the runway end contributed to aircraft damage and to the injuries to crew and passengers.

The pilot’s passenger briefing was only partly effective in that some passengers were engaged in other activities and did not assimilate the exit procedure, causing them to have difficulty opening the passenger door during the evacuation. In addition, the deceased passenger was not wearing his shoulder harness, which contributed  to the seriousness of his injuries due to the impact when the aircraft reached the bottom of the ravine and ultimately to his death in the post-impact fire.

Previous TSB recommendations A06-09 and A06-10 were issued to reduce the risk of post-impact fire in new production and existing production aeroplanes weighing less than 5700 kg. Responses to these recommendations received from TC have been rated as Unsatisfactory. As a result, there is a continuing risk of post-impact fire in impact-survivable accidents involving these aircraft.

In 2010, TSB published its Watchlist describing the safety problems that pose the greatest risk to Canadians. Among the safety issues identified, TSB noted that data critical to understanding how and why transportation accidents happen are frequently lost, damaged, or not required to be collected. While C-FMCB was equipped with an event recorder, it was not required to be equipped with certified flight recorders. When data recordings are not available to an investigation, this may preclude the identification and communication of safety deficiencies to advance transportation safety.

Findings as to Causes and Contributing Factors

  1. Runway conditions, the pilot’s takeoff technique, and possible shifting wind conditions combined to reduce the rate of the aircraft’s acceleration during the takeoff roll and prevented it from attaining takeoff airspeed.
  2. The pilot rejected the takeoff past the point from which a successful rejected takeoff could be completed within the available stopping distance.
  3. The steep drop-off and sharp slope reversal at the end of Runway 33 contributed to the occupant injuries and fuel system damage that in turn caused the fire. This complicated passenger evacuation and prevented the rescue of the injured passenger.
  4. The deceased passenger was not wearing the available shoulder harness. This contributed to the serious injuries received as a result of the impact when the aircraft reached the bottom of the ravine and ultimately to his death in the post-impact fire.

Findings as to Risk

  1. If pilots are not aware of the increased aerodynamic drag during takeoff while using soft-field takeoff techniques they may experience an unexpected reduction in takeoff performance.
  2. Incomplete passenger briefings or inattentive passengers increase the risk that they will be unable to carry out critical egress procedures during an aircraft evacuation.
  3. When data recordings are not available to an investigation, this may preclude the identification and communication of safety deficiencies to advance transportation safety.
  4. Although the runway at Pukatawagan and many other aerodromes are compliant with Aerodrome Standards and Recommended Practices (TP 312E), the topography of the terrain beyond the runway ends may increase the likelihood of damage to aircraft and injuries to crew and passengers in the event of an aircraft overrunning or landing short.
  5. TC‘s responses to TSB recommendations for action to reduce the risk of post-impact fires have been rated as Unsatisfactory. As a result, there is a continuing risk of post-impact fires in impact-survivable accidents involving these aircraft.
  6. The lack of accelerate stop distance information for aircraft impedes the crew’s ability to plan the takeoff-reject point accurately.

Other finding

  1. Several anomalies were found in the engine’s power control hardware. There was no indication that these anomalies contributed to the occurrence.

Safety Action Taken

Missinippi Airways

The following has been reviewed with crews

  • Pilot takeoff technique- short field/soft field;
  • Weather conditions and its effects on flight at Pukatawagan in particular;
  • Accelerate/stop parameters;
  • Confirmation that passengers wear their seatbelts and shoulder harnesses.

The company has implemented a new short-field take-off procedure that follows the normal take-off procedure in the C208B POH. The company will also have more emphasis on short/soft field take-off/landing procedures in future ground schools for allaircraft types operated.

The matter of the engine power control hardware has been addressed through the company quality assurance program and the following action has taken place

  • Parts catalogue print outs of engine controls will be installed in each aircraft
  • Inspection/task binder for quick reference of parts required
  • Where a maintenance action that requires engine removal/ installation, a checklist will be used outlining specific checks to be completed concerning dual inspection and parts usage for engine installation. This form is to be filled out and signed by the person completing the dual inspection.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 21 June 2012.

Appendix A – Cabin Seating Arrangement, Cessna 208B

Cabin Seating Arrangement, Cessna 208B

Appendix B – Performance Results Cessna 208B

208B with Pod
Pressure Altitude 960 ft
Weight 8000 lb
OAT 25 °C
Wind Speed 13 kts
Wind Direction 290
Runway 33
Takeoff Ground Roll Flaps 20°
73 KTAS
Interpolated Ground Roll 1258 ft
HW Correction 10.0 kts 1144 ft
Gravel Correction 11% 1270 ft
Landing Ground Roll Flaps FULL
79 KTAS
Interpolated Ground Roll 922 ft
HW Correction 10.0 kts 839 ft
Gravel Correction 18% 989 ft
Total Ground Roll Distance Here: 2259 ft

Note: Interpolated ground roll results for takeoff, flaps 20° and landing, flaps full, were obtained based on test results. Results for accelerate-stop, and landing, flaps up, were not available.

Appendix C – TSB Data – Runway Overrun Occurrences – January 2002 to May 2011

File No. Date Location Overrun area Aircraft type Damage Injuries
A02A0107 10/09/2002 Gander, NL Displaced threshold DC-8 None None
A03W0047 07/03/2003 Fort McMurray, AB Gravel and snow Beech 200 None Minor
A04O0188 14/072004 Ottawa, ON Grass overrun area Embraer 145 regional jet None None
A04O0336 16/12/2004 Oshawa, ON Overrun area/fence Shorts SD3-60 Substantial Serious
A04Q0197 23/12/2004 Sherbrooke, PQ Overrun area/snow Falcon 20 None None
A05A0035 15/03/2005 St. Anthony, NL Graded, level, gravel surface Merlin SW4 None None
A05O0105 27/05/2005 Chapleau, ON Gravel overrun area Grumman G-159 Gulfstream None None
A05H0002 02/08/2005 Toronto, ON Gully overrun area Airbus A-340-313 Destroyed Serious
A05A0102 12/08/2005 Kildare Capes, PEI Treed overrun area Beech 19a Musketeer Substantial Serious
A05O0257 15/11/2005 Hamilton, ON Overrun area Gulfstream 100 None None
A06O0015 21/01/2006 Hamilton, ON Overrun area Boeing 707-330b None None
A06C0117 23/07/2006 Sachigo Lake, ON Gravel threshold and 300-400 feet of clearway Hawker Siddeley HS 748 Minor None
A06Q0190 26/11/2006 Montréal, PQ 600 feet into overrun area Learjet 35a Substantial None
A06W0250 29/12/2006 Carat lake, NU Overrun area- embankment Douglas C-54 Substantial Minor
A07P0008 09/01/2007 Prince George, BC Overrun area 60 feet/snow Learjet 25B Substantial Minor
A07A0029 31/05/2007 Gander, NL Overrun area 400 feet Volga Dnepr AN124 None None
A07C0103 15/06/2007 Red Lake, ON Gravel overrun/30 feet Cessna 680 None None
A07P0340 04/10/2007 Comox, BC Displaced threshold 500 feet Boeing 737-700 None None
A08W0001 07/01/2008 Fort Smith, NT Runway overrun area 367 feet BAE Jetstream 3212 Minor None
A08O0035 17/02/2008 Ottawa, ON Runway overrun area 200 feet snow Boeing 737-700 None None
A08O0333 14/12/2008 North Bay, ON Runway overrun area 250 feet snow DeHavilland DHC 8-100 None None
A09O0176 16/08/ 2009 Sault Ste Marie, ON Runway overrun area 100 feet McDonnell Douglas CF-18 Unknown None
A10C0012 22/01/ 2010 Winnipeg, MB Runway side Canadair RJ700 None None
A10A0032 24/03/2010 Moncton, NB Runway overrun 40 feet mud Boeing 727-200 None None
A10H0004 16/06/2010 Ottawa, ON Runway overrun 500 feet Embraer 145 Minor Minor
A10A0094 10/09/2010 Halifax, NS Runway overrun area F86E Sabre Jet Minor None
A10O0111 02/06/2010 Oshawa, ON Runway overrun area 233 feet Fairchild SA-227-AC None None
A10P0250 04/08/2010 Abbotsford, BC Closed runway area Boeing 737-600 None None
A10C0165 15/09/2010 Steinbach, MB Runway overrun – ditch Cessna 182B Substantial None
A10A0114 30/10/2010 Gander, NL Runway overrun area Gulfstream G IV None None
A10Q0221 18/12/2010 Sanikiluaq, NU Runway side Swearingen Metro SA226-TC Substantial None
A11O0081 03/01/2011 Kincardine, ON Runway overrun area – trees Piper PA28 Substantial None
A11C0020 12/02/2011 Winnipeg, MB Runway overrun area Canadair CL-600 RJ None None
A11C0048 03/04/2011 Kindersley, SK Runway overrun area 30 feet snow Cessna 172M Substantial None
A11C0057 18/04/2011 Steinbach, MB Runway overrun area – ditch Cessna 152 Substantial None
A11C0065 29/04/2011 Shoal Lake, MB Runway overrun area Cessna 177B Substantial Minor

  1. All times Central Daylight Time (Coordinated Universal Time minus 5 hours).
  2. The investigation determined that the prevailng temperature at Pukatawagan Airport was approximately 25°C.

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Aviation Reports – 2009 – A09Q0203

| Transportation Safety Board Reports | May 2, 2012

Transportation Safety Board of Canada

Aviation Reports – 2009 – A09Q0203

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Controlled Flight into Terrain
Exact Air Inc. Beech A100 C-GPBA
3 nautical miles NW
Chicoutimi/Saint–Honoré Airport, Quebec
09 December 2009

Report Number A09Q0203

Synopsis

The Beech A100 (registration C–GPBA, serial number B–215) operated by Exact Air Inc. as flight ET822 was on an instrument flight rules flight between Val–d’Or and Chicoutimi/Saint–Honoré, Quebec, with 2 pilots and 2 passengers on board. At 2240 Eastern Standard Time, the aircraft was cleared for an RNAV (GNSS) Runway 12 approach and switched to the aerodrome traffic frequency. At 2250, the International satellite system for search and rescue detected the aircraft’s emergency locator transmitter signal. The aircraft was located at 0224 in a wooded area approximately 3 nautical miles from the threshold of Runway 12, on the approach centreline. Rescuers arrived on the scene at 0415. The 2 pilots were fatally injured, and the 2 passengers were seriously injured. The aircraft was destroyed on impact; there was no post crash fire.

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Table of Contents

  • 1.0 Factual Information
  • 1.1 History of the Flight
  • 1.2 Wreckage and Impact Information
    • 1.2.1 General
    • 1.2.2 Damage to the Aircraft
    • 1.2.3 Fire
    • 1.2.4 Other Damage
  • 1.3 Survival Aspects
  • 1.4 Meteorological Information
  • 1.5 Crew Information
    • 1.5.1 General
    • 1.5.2 Task-induced Fatigue
  • 1.6 Company Information
    • 1.6.1 General
    • 1.6.2 Standard Operating Procedures
    • 1.6.3 Crew Training
  • 1.7 Aircraft Information
    • 1.7.1 General
    • 1.7.2 Altimeters
    • 1.7.3 Emergency Locator Transmitter
    • 1.7.4 Autopilot
    • 1.7.5 Terrain Awareness Warning System
    • 1.7.6 TSB Laboratory Examination and Analysis
  • 1.8 Aerodrome Information
    • 1.8.1 General
    • 1.8.2 Aircraft Rescue and Firefighting Service
    • 1.8.3 Runway and Approach Lights/Runway Lights
    • 1.8.4 Runway Conditions
    • 1.8.5 Communications
  • 1.9 Tests and Research
  • 1.10 Instrument Approach Information
    • 1.10.1 General
    • 1.10.2 Regulatory Overview
    • 1.10.3 Instrument Approach Design
    • 1.10.4 Instrument Approach Depiction
  • 1.11 Instrument Approach Techniques
    • 1.11.1 General
    • 1.11.2 Step-down Descent
    • 1.11.3 Stabilized Constant Descent Angle
  • 1.12 Controlled Flight into Terrain
  • 1.13 Approach and Landing Accidents
    • 1.13.1 General
    • 1.13.2 Recommendations Concerning Company Policies
    • 1.13.3 Recommendations Concerning SOPs
    • 1.13.4 Recommendations Concerning Training
    • 1.13.5 Recommendations Concerning Decision Making
    • 1.13.6 Recommendations Concerning CVRs and FDRs
    • 1.13.7 Recommendations Concerning Autopilot
    • 1.13.8 Recommendations Concerning Radio Altimeter
    • 1.13.9 Recommendations Concerning Instrument Approach Procedure Design
    • 1.13.10 Recommendations Concerning the Depiction of Instrument Approach Charts
    • 1.13.11 Recommendations Concerning the SCDA Approach Technique
    • 1.13.12 FSF ALAR Tool Kit
    • 1.13.13 Other Approach and Landing Accident Reduction Initiatives
    • 1.13.14 Approach and Landing Accidents in Canada
  • 1.14 ICAO Risk Assessment Matrix
  • 2.0 Analysis
  • 2.1 The Flight
  • 2.2 Descent below MDA
    • 2.2.1 General
    • 2.2.2 Factors, Influences and Scenarios
  • 2.3 Risk Assessment and Mitigation of Non-precision Approaches
  • 2.4 ALARisk Mitigation Actions
    • 2.4.1 General
    • 2.4.2 Instrument Approach Design
    • 2.4.3 Instrument Approach Depiction
    • 2.4.4 Stabilized Constant Descent Angle Technique
    • 2.4.5 FSF Recommendations
    • 2.4.6 FSF ALAR Task Force Tool Kit
  • 3.0 Conclusions
  • 3.1 Findings as to Causes and Contributing Factors
  • 3.2 Findings as to Risk
  • 3.3 Other Findings
  • 4.0 Safety Action
  • 4.1 Action Taken
    • 4.1.1 Exact Air Inc.
    • 4.1.2 NAV CANADA
  • 4.2 Safety Action Required
    • 4.2.1 Design and Depiction of Canadian Instrument Approach Procedures
    • 4.2.2 Stabilized Constant Descent Angle (SCDA)
  • 4.3 Board Concern
    • 4.3.1 FSF ALAR Task Force Recommendations
  • Appendix A — RNAV (GNSS) Runway 12 – CAP
  • Appendix B — Graphical Forecast Area
  • Appendix C — Examples of Descent Profiles
  • Appendix D — Safety Risks (ICAO Doc 9859 AN/474)

1.0 Factual Information

1.1 History of the Flight

The 2 pilots were based in Baie–Comeau, Quebec, and normally flew out of the Exact Air Inc. base at Baie–Comeau Airport (CYBC). At 1130 1, the crew was called to fly from Chicoutimi/Saint–Honoré (CYRC) Airport to Val–d’Or (CYVO) and return. The crew departed Baie Comeau by car at around 1300, arriving at CYRC at approximately 1630. The plan was to leave at 1800 with 7 passengers for CYVO, then return to CYRC with 2 passengers. The aircraft took off from CYRC at 1800 and landed at CYVO at 1933.

Refuelling was delayed at CYVO and was not completed until 2105. The aircraft was filled with approximately 2500 pounds of fuel, roughly 1 h 52 minutes of extra fuel above the minimum required by regulation using the Bagotville (CYBG) Airport as an alternate.

The copilot contacted the Québec flight information centre (FIC) for an update on the weather forecast and conditions at CYBG. The 2 passengers boarded the aircraft and sat in the last 2 side–by–side seats located at the rear of the aircraft. The flight departed CYVO at 2133 and climbed to its cruising altitude of flight level 190. The copilot was the pilot flying (PF) 2, while the pilot–in–command assumed the duties of the pilot not flying (PNF). 3

At 2215, the crew contacted the Québec FIC for the latest weather conditions, as well as the runway conditions at CYRC, Roberval (CYRJ) and CYBG. The latest available runway conditions for CYRC had been issued at 1625 and at 1642 for CYRJ. Recent runway conditions were only available for CYBG.

At 2230, the crew was issued the CYBG altimeter setting which was 29.34 inches of mercury; the aircraft began its descent a few minutes later. At 2240, the crew was cleared for the RNAV Runway 12 approach via the XESUT fix (Figure 1).

At 2245, the flight was transferred to 118.4 MHz. As the CYRC tower was closed at the time, the frequency was to be used as the aerodrome traffic frequency (ATF). At that point, the aircraft was flying between the XESUT and RABAD fixes, at an altitude of 5800 feet above sea level (asl) 4 at a ground speed of 250 knots.

Figure 1. RNAV (GNSS) Runway 12 approach course
Figure 1. RNAV (GNSS) Runway 12 approach course ↑

At 2246, the aircraft passed the RABAD intermediate approach fix at an altitude of 3900 feet asl with a ground speed of 200 knots.

At 2249, the crew transmitted on the ATF frequency that it had reached RABAD and would be on final shortly for Runway 12. However, according to the radar data, this transmission corresponds to the moment at which the aircraft passed the ESRIX final approach fix. At that point, the aircraft was at an altitude of 1100 feet asl with a ground speed of 100 knots, which, under the existing conditions, was consistent with an indicated airspeed of approximately 130 knots.

The last radar position was recorded at 2249, 0.5 nautical miles (nm) after crossing the ESRIX fix, still at 1100MHzfeet asl, i.e. approximately 600 feet above ground level (agl), at a distance of 4.5 nm from the threshold of Runway 12.

The company was expecting the aircraft’s arrival. A few minutes after the 2249 call from C–GPBA on the 118.4 MHz frequency, the runway lights were lit.

At 2250, the Canadian Mission Control Centre (CMCC) received a message that the COSPAS SARSAT 5 system had detected an emergency locator transmitter (ELT) signal on the 406 MHz frequency. The signal originated from C–GPBA and steps were taken to find the emergency contact person.

At 2306, the CMCC contacted Exact Air Inc. personnel, who confirmed that C–GPBA was on a flight from CYVO to CYRC, that the runway lights were lit, but that the aircraft had not yet landed.

At 2318, the CMCC contacted the Montreal area control centre (ACC) to check the position of C–GPBA. Montreal ACC then contacted the controller at the Bagotville terminal to check on the status of flight ET822. The ACC was advised that the aircraft had been switched over to the ATF frequency at 2245 and that its last radar position corresponded to 4 nm on final approach to Runway 12. However, the crew had not yet confirmed that it was on the ground at CYRC. The rescue coordination centre must be informed when no communication has been received from an aircraft within a period of 30 minutes after the time a communication should have been received 6. Five minutes still remained before the 30–minute uncertainty phase would have been reached.

At 2325, the Sûreté du Québec (Quebec provincial police) was informed that the aircraft might have crashed in the final approach area of Runway 12 at Saint–Honoré Airport. A command post was set up at Saint–Honoré Airport and search efforts were coordinated with volunteers, including company personnel, to deploy snowmobiles, sleds and ambulances.

At 2346, the first call from a cell phone belonging to one of the passengers was received by the 911 emergency services, but communication was lost several times. Two passengers were in the aircraft, which was inverted, and both pilots were unconscious. At that time, it was not possible to determine the cell phone’s location.

By 0130, the location coordinates of the cell phone used by the passenger had been determined and were passed on to the Sûreté du Québec. Snowmobilers were sent towards this position. However, it was 5 nm to the southeast of the aircraft.

The Joint Rescue Coordination Centre (JRCC) dispatched a Hercules aircraft from the Trenton, Ontario, base. The Hercules arrived on the scene at approximately 0215 and, by homing in on the 121.5 MHz ELT signal, was able to locate the aircraft at 0224. At 0315, flares were deployed to help the snowmobilers find the aircraft on the ground.

At approximately 0415, rescuers on the ground located the aircraft in a wooded area about 3 nm from the threshold of Runway 12. A Griffon helicopter dispatched from the Bagotville base arrived at the accident site at 0430. The survivors (the 2 passengers) were transported by helicopter to the hospital; they were seriously injured. Both pilots were killed on impact with the ground.

1.2 Wreckage and Impact Information

1.2.1 General

The initial point of impact with the treetops occurred 170 feet north of the Runway 12 final approach course, approximately 3 nm before the runway, which corresponds to the approximate position of the OTUTI intermediate approach fix (Appendix A).

From its last radar position, at an altitude of 1100 feet asl and travelling at a ground speed of 100 knots, the aircraft covered a distance of 1.59 nm before striking treetops at a height of 525 feet asl. The average descent rate was, therefore, approximately 600 feet per minute.

After initial contact with the treetops, the aircraft travelled 340 feet before the right wing was severed by large trees. The aircraft then began a pronounced roll to the right, hitting trees that partially severed its left wing. It then struck the ground and tumbled, finally coming to a rest inverted, 300 feet away (Photo 1). The wreckage was transported to the TSB Laboratory.

Photo 1. Aircraft wreckage
Photo 1. Aircraft wreckage ↑

1.2.2 Damage to the Aircraft

The nose of the aircraft sustained heavy damage upon impact with the ground. The fuselage was breached in spots due to the compressive forces exerted on the right side and the tensile forces exerted on the left. Only the passenger cabin retained sufficient shape necessary for survival.

1.2.3 Fire

The aircraft’s fuel tanks, located in the wings, ripped open when the wings were severed following impact with the trees. Most of the fuel was spilled before the aircraft came to a stop. There was no post–impact fire.

1.2.4 Other Damage

Damage to the environment was limited to the trees that were struck and the approximately 900 litres of fuel spilled on the snow–covered ground and surrounding vegetation.

1.3 Survival Aspects

The cockpit was severely compressed on impact with the ground and, as a result, there was insufficient space remaining to allow the 2 pilots to survive. The passenger cabin was damaged by compressive and tensile forces, causing a significant breach in the structure. However, the passenger cabin space preserved its initial shape.

Six of the 8 seats were ripped from their moorings. The seat occupied by the passenger in the left rear position became detached, struck the passenger on the right side then came to rest at the front of the cabin, with the passenger still attached. The seat occupied by the passenger in the right rear position remained anchored to the structure with the passenger still attached.

The main cabin door was obstructed by tree branches and could not be opened. The emergency exit above the right wing was jammed as a result of fuselage deformation and could not be used either. No emergency lights were available to the passengers, who huddled together and used sheepskin seat covers to protect themselves against the cold while waiting for help to arrive.

A passenger made several 911 emergency calls on a cell phone to report the aircraft accident.

To improve the safety of Canadians, the Canadian Radio–television and Telecommunications Commission (CRTC) required wireless service providers to improve their 911 services by 01 February 2010. 7 These enhanced 911 services (E911) were to make it easier to locate a person making a 911 call from a cell phone, particularly in an emergency when the person cannot speak or indicate his or her position.

Cell phone providers “use the Global Positioning System (GPS) or triangulation technology and then automatically transmit the caller’s location to the call centre operator. This allows emergency responders to determine a caller’s location generally within a radius of 10 to 300 metres from the cellphone.” 8

1.4 Meteorological Information

At 1900, a deep low pressure system over Lake Huron was moving in a northeasterly direction towards the Val–d’Or area and Lac St–Jean at approximately 20 knots. As a result, all of southern Quebec was covered by a layer of cloud from 2000 feet to 20 000 feet asl, accompanied by light to moderate snow showers and areas of scattered heavy snow showers, all of which occasionally reduced visibility to 0.25 statute miles (sm) (Appendix B).

No aviation routine weather reports (METAR) are available at the CYRC airport.

At 2300, observations at CYBG, approximately 15 nm south of CYRC, indicated winds 110° True (T) at 21 knots gusting to 31 knots with a ground visibility between 3⁄4 and 1 1⁄4 sm in light snow and blowing snow. The ceiling was at 4200 feet agl, the surface temperature −7°C, the dew point −8°C and the altimeter setting 29.32 inches. Radar images from Lac au Castor (WMB) showed a significant area of precipitation in the CYRC area between 2240 and 2250.

The weather available to the crew was the amended aerodrome forecast (TAF) for CYBG issued at 1655, valid from 1600 on 09 December 2009 until 1600 on 10 December 2009, indicated the following: winds 090° T at 25 knots gusting to 40 knots, the ground visibility 6 sm in light snow and blowing snow, with a ceiling at 3000 feet agl. Between 1600 and 2100, temporary conditions may reduce the visibility to one sm in light snow and blowing snow, with obscured sky conditions that would result in a vertical visibility of 800 feet. From 2100 the visibility was forecast as 1⁄2 sm in moderate snow and blowing snow and a vertical visibility of 500 feet with a temporary condition between 2100 and 1000 the next day of 1⁄4 sm in heavy snow and blowing snow and a vertical visibility of 200 feet.

In accordance with the instrument flight rules (IFR), the flight plan included an alternate airport, which in this case was CYBG. According to the Canadian Aviation Regulations (CARs) 9, to qualify as an appropriate alternate, the weather at CYBG should have forecast conditions at or above the minimum specified in the Canada Air Pilot (CAP), i.e. one sm at the expected time of arrival. When the weather conditions were updated before departure from CYVO, the CYBG TAF did not meet the CARs requirements for an alternate airport, because the visibility was forecast as low as 1⁄4 sm for the specified period.

Ground visibility at night is not necessarily representative of flight visibility. Depending on the type of lighting, the distance at which a light can be seen in flight may be twice that as could be seen on the ground. Some countries, such as those of the European Union 10, have recognized this phenomenon and have increased the ground-observed visibility to establish a converted visibility value. This converted value is used to determine minima for instrument approaches.

1.5 Crew Information

1.5.1 General

The pilot–in–command (PIC) held a valid airline transport pilot licence issued in September 2008 and had approximately 3500 hours of total flying time, including 1000 hours on the Beech A100 (BE10). The PIC had been working for the company since November 2007 and had completed a pilot proficiency check (PPC) on the BE10 in July 2009. The PIC was also a flight instructor on the BE10.

The copilot had completed his initial flight training at CYRC and held a valid commercial pilot licence issued in September 2006 along with a group I instrument rating. The copilot had been working for the company since March 2008 and completed a pilot proficiency check (PPC) on the BE10 in April 2009. The copilot had accumulated approximately 1000 hours of total flying time, of which 150 hours were on the BE10.

The flight crew was licenced and qualified for the flight in accordance with existing regulations.

The pilot and copilot were critically injured and died immediately following the accident. Toxicology testing of the pilots did not reveal any pre–existing conditions or the presence of any substance that might have impeded the pilots’ performance. A review of the pilots’ medical records by Transport Canada (TC) did not reveal any medical factors or pathologies that could have affected the performance of their duties.

1.5.2 Task–induced Fatigue

In the days preceding the accident, the pilot and the copilot had benefited from 2 and 3 days off, respectively, followed by 1 day of flying together. On the day before the accident, they had completed 2 return flights between Baie–Comeau and Rimouski, starting their work day at 1430 and finishing at 2335.

On the day of the accident, the crew was called at 1130 for a flight from CYRC to CYVO. Take off was scheduled for 1800, with the flight returning to CYRC at approximately 2200. At the start of their work day, there was no indication that the crew might be fatigued due to a lack of sleep or any health–related issue. Moreover, the crew had benefitted from a period of rest in accordance with the CARs. The crew ate a meal at Saint–Honoré Airport before initiating pre–flight preparations.

The crew travelled from Baie–Comeau to Saint–Honoré by car, covering the 325–km distance in 4 hours, in snow showers and blowing snow. As sunset was at 1549, part of the trip and all of the flight took place in darkness. The pilots flew manually on the outbound and return legs in low visibility and conditions of low–altitude turbulence.

Performing tasks related to driving a car and piloting an aircraft under such conditions requires heightened mental concentration and visual attention. Such intense concentration over an extended period of time typically results in task–induced fatigue that negatively affects visual and cognitive performance. The decreased cognitive performance in turn has a negative impact on working memory. Working memory enables information to be temporarily stored for the purpose of making mental calculations. 11

1.6 Company Information

1.6.1 General

Exact Air Inc. holds a valid air operator’s certificate. Its headquarters are located at CYRC. In addition to CYBC, the company operates out of 3 other bases located at Havre Saint Pierre, Port–Menier and Sept–Îles.

At the time of the occurrence, Exact Air Inc. operated a fleet of 42 aircraft comprised of the following types: Beech A100 (BE10), Piper PA–31, Piper PA–34, Cessna 402, Cessna 310, Cessna 182, Cessna 172 and Cessna 152. Depending on the type of aircraft used, operations were conducted pursuant to Subpart 3, Part VII of the CARs. During the occurrence flight, the aircraft was operated as an air taxi under Subpart 3. The BE10 (C–GPBA) was based in Saint–Honoré, whereas the crew normally worked out of the base at CYBC. As such, the crew did not fly this BE10 very often.

Exact Air Inc. uses a Type D (self–dispatch) operational control system 12 under which the operations manager delegates operational control of the flight to the pilot–in–command, but retains responsibility for all flight operations. Additionally, a person who is qualified and knowledgeable in the air operator’s flight alerting procedures shall be on duty or available when IFR or night VFR flight operations are being conducted. Exact Air Inc. had a person on duty for the occurrence flight.

1.6.2 Standard Operating Procedures

The company’s operations manual and standard operating procedures (SOP) comply with the Commercial Air Services Standards (CASS); however the SOPs are not subject to TC approval.

The SOPs state that during an instrument approach, the PF manoeuvres the aircraft to remain within the limits of the approach and focuses his attention exclusively inside the aircraft. The PNF focuses his attention both inside and outside the aircraft and must complete the following actions:

  • Make standard calls
  • Advise of any abnormal indications
  • Perform timing requested by the PF
  • Call out “Vertical Contact” when the ground is sighted
  • Call out “Approach Lights” or “Runway in Sight” when these visual references are observed, which will ensure that the aircraft can be safely landed

The Before landing checklist must be completed before the FAF. Generally, the PNF makes the calls, otherwise they are made by the PF. For the RNAV (GNSS) Runway 12 approach where no deviations are encountered, the following calls are required to be made:

[Translation] Situation Standard Call Transition 18 000 feet ”Transition, altimeter … indicating… crosscheck“ 1000 feet above cleared altitude Example: 15 000 for 14 000 100 above cleared altitude ”100 to go“ At FAF FAF: altitude, no flags“ 1000 feet before minimum ”1000 above“ 100 feet before minimum ”100 above“ Visual contact ”Vertical Contact“ ”Runway in Sight,“ ”Approach Lights“ Minimum altitude ”Altitude Contact“ or ”No Contact“ Missed approach point (MAP) ”Minimum Contact“ or ”No Contact“ If contact ”Continue“ If no contact ”Go around“

As the aircraft was not equipped with a cockpit voice recorder (CVR), it was not possible to determine if these calls were made in accordance with the SOPs.

1.6.3 Crew Training

Exact Air Inc. has an operations specification 13 authorizing GPS–based instrument approaches for which the crew had been trained as per the CASS.

According to the CASS14 controlled flight into terrain (CFIT) avoidance training must be provided during initial and biennial ground training, which the crew had received. Such training must essentially cover:

  • Factors that may lead to CFIT accidents and incidents
  • Operational characteristics, capabilities, and limitations of GPWS (if applicable)
  • CFIT prevention strategies
  • Methods of improving situational awareness
  • Escape manoeuvre techniques and profiles applicable to the aeroplane type

The International Civil Aviation Organization (ICAO) states that the fundamental purpose of crew resource management (CRM) training is “to improve flight safety through the effective use of error management strategies in individual as well as systemic areas of influence” and proposes the integration of threat and error management (TEM) into CRM15

Further to TC‘s response to recommendation A95–11, issued by the TSB in 1995, CRM training is now required by air transport operators operating pursuant to section 705 of the CARs. However, this training is not required for commuter operations pursuant to section 704 of the CARs or an air taxi service pursuant to section   of the CARs.

Further to the CFIT accident involving a Beech King Air at Sandy Bay, Saskatchewan, on 07 January 2007, the TSB made recommendation A09–02:

In light of the risks associated with the absence of recent CRM training for air taxi and commuter crew members, the Board recommended that:

The Department of Transport require commercial air operators to provide contemporary crew resource management (CRM) training for Canadian Aviation Regulations (CARs) subpart 703 air taxi and CARs subpart 704 commuter pilots.

(A09–02)

The CARs still do not require CRM training for air taxi or commuter operators and, consequently, the pilots of C–GPBA had not received any.

In its response on 14 January 2010, TC agreed to the recommendation in principle and expected to present a risk assessment and any related recommendation to the Civil Aviation Regulatory Committee (CARC) in the spring of 2010. The resulting recommendation from CARC will trigger the rulemaking process.

In its response on 21 January 2011, TC indicated that it had completed its risk assessment. The CARC agreed to a balanced approach, including acceptance of TSB Recommendation A09–02, a regulatory measure, training and guidelines. The project plan is currently being reviewed in light of existing priorities.

The risk assessment conducted by TC validated the TSB‘s finding as to risk regarding the absence of recent CRM training and broadened the scope of the safety deficiency to include commercial single–pilot operations. The risk assessment also concluded that current training issues extended beyond CARs 703 and 704 pilots, and recommended better defined training requirements and integrating contemporary CRM into existing training requirements.

On 19 September 2011, the Civil Aviation Regulatory Committee directed that a Focus group be established as soon as possible in the fall to address this issue. This newly formed focus group met for the first time on 23 January 2012. TC has continued to make progress in implementing TSB Recommendation A09–02. The accepted course of action, if implemented, would substantially reduce or eliminate the deficiency identified in Board Recommendation A09–02. The TSB considers that TC‘s response indicates a Satisfactory Intent.

1.7 Aircraft Information

1.7.1 General

The aircraft was certified and equipped in compliance with existing regulations. 16 Maintenance was carried out by Exact Air Inc.‘s approved maintenance organization (AMO) in accordance with a maintenance schedule 17 approved by TC. The aircraft weight and centre of gravity were within the limits prescribed by the manufacturer.

1.7.2 Altimeters

Pressure altimeters are calibrated to indicate true altitude under international standard atmosphere (ISA) conditions. Any deviation from ISA will result in an erroneous reading on the altimeter. In a case when the temperature is lower than the ISA, the true altitude will be lower than the indicated altitude. Therefore, temperature corrections for cold weather must be added to the published altitudes on instrument approach charts when the temperature is below 0°C.

As the surface temperature was −7°C, a correction needed to be made to the approach fix crossing minimum altitudes as well as to the minimum descent altitude (MDA). A correction of 67 feet needed to be added to the published altitude at the final approach fix (FAF), a correction of 40 feet in the minimum published altitude at the OTUTI fix and a correction of 30 feet to the MDA.

Normally, the instrument approach procedure is conducted using the current CYRC altimeter setting. At the time of the approach, however, the CYRC control tower was closed and no advisory service was available. However, the instrument approach allows the use of the CYBG altimeter setting with the application of a 30–foot correction to the published altitudes.

Therefore, with the corrections for cold weather and the use of the CYBG remote altimeter setting, the corrected FAF crossing altitude was 1397 feet, the corrected minimum published altitude to the OTUTI fix was 970 feet asl and the corrected MDA was 920 feet asl.

The investigation did not permit to determine whether these corrections had been applied. In addition, the 2 altimeters were not equipped with a target altitude bug nor was it a requirement.

The C–GPBA was equipped with a radio altimeter. Its decision height bug had been set to approximately 1500 feet agl, which did not correspond to any specific altitude for the RNAV (GNSS) Runway 12 approach. When the agl height falls below the bug setting, the “DH” light on the radio altimeter illuminates. The CARs do not require that SOPs include directives on the use of radio altimeters for non–precision approaches. No such procedures were in place.

1.7.3 Emergency Locator Transmitter

The aircraft was equipped with a KANNAD ELT, model 406AF-COMPACT, serial number 259215, which could transmit on both 121.5 MHz and 406 MHz frequencies. The emergency locator transmitter (ELT) was not damaged by the accident and it activated on impact. However, the antenna installed on the back of the cabin was damaged.

Owners and operators are responsible for registering beacons with the Canadian Beacon Registry 18. C–GPBA’s ELT was not registered. Consequently, emergency contact information was not available. Additional efforts were required of CMCC staff to locate and contact a person responsible for flight following in case of an emergency.

1.7.4 Autopilot

On 19 November 2009, C–GPBA’s autopilot became inoperative as a result of pitch oscillations. The aircraft was returned to service without an autopilot as per the company’s Maintenance control manual (MCM) and the CARs.

1.7.4.1 Cockpit Voice Recorders (CVR)

The CARs state that 19 “no person shall conduct a take–off in a multi–engine turbine–powered aircraft that is configured for six or more passenger seats and for which two pilots are required by the aircraft type certificate or by the subpart under which the aircraft is operated, unless the aircraft is equipped with a cockpit voice recorder.”

C–GPBA was a multi–engine, turbine–powered aircraft configured for 8 passengers. Its type certificate 20 allowed it to be operated by a single pilot. The aircraft was being used pursuant to Subpart 703 of the CARs,21 which requires the presence of 2 pilots when operating an aircraft with passengers in IMC flight. However, Exact Air Inc. held an operations specification22 issued by TC that permits the operation of an aircraft with passengers on board in IMC flight without a second–in–command. In such a case, the CARs requirements governing pilots23 and additional equipment24, such as a functioning autopilot, must be respected. As the autopilot on C–GPBA was not operational, a second pilot was required.

Differing interpretations of the CVR requirement led some Quebec operators to challenge its application by TC before the courts. The Federal Court of Appeal ruled for the operators which allowed them to operate BE10s in commercial air taxi service without a CVR.

According to TC, the court’s interpretation of the wording ran counter to the intention of the CARs. In November 2009, the Canadian Aviation Regulation Advisory Council (CARAC) developed a Notice of proposed amendment (NPA) to the CARs. The aim was to clarify that a CVR is always required when an aircraft of this type, configured for 6 or more passenger seats, is operated by 2 pilots. However, the CARs still had not been amended as of the beginning of 2012.

1.7.5 Terrain Awareness Warning System

1.7.5.1 Garmin TAWS

Two GPS devices (Garmin GNS–530 and GNS–430) were installed on the event aircraft in compliance with the supplemental type certificates25 of Garmin International and existing regulations. C–GPBA was Exact Air Inc.‘s first BE10 to be equipped with GPS devices, but these did not incorporate either the wide area augmentation system (WAAS) or the terrain awareness warning system (TAWS). However, the Garmin 530W installed on the company’s other BE10s include TAWS.

One of the features of the Garmin 530W TAWS is the forward looking terrain avoidance (FLTA) used to generate alerts and warnings when the aircraft is projected to come within a minimum established clearance value of terrain or obstacles. Any potential impact points are then depicted on the display.

FLTA provides an amber caution alert when the predicted impact is in approximately 30 seconds and is accompanied by one of several caution aural messages. When the estimated impact is in approximately 15 seconds, a red warning alert is generated with an associated “Pull Up” aural message.

The premature descent alerting (PDA) feature detects that the aircraft is significantly below the normal approach path to a runway and generates an amber caution alert with a “Too Low Terrain” aural message.

The Garmin’s 530W TAWS satisfies TSO–C151b Class B requirements for certification.

1.7.5.2 United States

The Federal Aviation Administration (FAA) in the United States has required all commercially operated turbine-powered airplanes with 6 or more passenger seats26 to be fitted with a TAWS since 29 March 2001. According to the FAA‘s Instrument Procedures Handbook,27 pilots can reduce their exposure to CFIT accidents by identifying risk factors and remedies before each flight. An additional measure involves equipping aircraft with TAWS. According to the FAA, this precaution alone could reduce CFIT accidents by over 90%.

1.7.5.3 European Economic Community

European Economic Community (EEC)28 regulations require that operators install TAWS on all turbine powered aeroplanes having a maximum certificated take–off mass in excess of 5700 kg or a maximum approved passenger seating configuration of more than 9 seats.

1.7.5.4 Australian Transport Safety Bureau

The Australian Transport Safety Bureau (ATSB) issued a recommendation29 on 09 March 2006 concerning the installation of TAWS on aircraft weighing less than 5700 kg to improve terrain awareness and, consequently, reduce the risk of CFIT accidents.

1.7.5.5 Transportation Safety Board of Canada

Following the CFIT accident involving a Hawker Siddeley northwest of Sandy Lake, Ontario, on 10 November 1993, the TSB issued recommendation A95–10:

Most turbo–prop aircraft, some carrying dozens of passengers, continue to operate without the added safety protection of GPWS. Therefore, the Board recommended that:

The Department of Transport require the installation of GPWS on all turbine–powered, IFR–approved, commuter and airline aircraft capable of carrying 10 or more passengers.

(A95–10)

In its response of 14 December 2005, TC noted that TAWS, the technology that supersedes GPWS, would certainly overcome the deficiencies inherent in GPWS. There is a strong possibility that the regulations will be published in Part I of the Canada Gazette in late 2005 or early 2006. In the package of new regulations, there are also regulations under CARs 605 requiring turbine–powered aeroplanes configured with more than 6 passenger seats to be equipped with Class B TAWS.

In its response of 07 February 2007, TC said the regulations were expected to be pre–published in the Canada Gazette Part I by April or May 2007, but this date has been pushed back to sometime in the fall of 2007.

In its response of 13 August 2008, TC stated that it is possible that the regulations may be published in the Canada Gazette Part I in 2008.

In its response of 15 February 2010, TC indicated that its CARAC consultation of the TAWS related NPAs and the drafting of regulations by Justice Canada were complete.

The proposed regulatory changes were pre–published on 03 December 2011, in the Canada Gazette, Part 1, Volume 145, No. 49. The proposed regulatory amendments would introduce requirements for the installation of TAWSs in private turbine–powered aircraft configured with six or more passenger seats, excluding pilot seats, and in commercial aircraft configured with six or more passenger seats, excluding pilot seats. Operators would have 2 years from the date on which the regulations come into force to equip their aircraft with TAWS.

The proposed regulatory amendment brought forward by TC, if adopted and implemented, will substantially reduce the safety deficiency identified in Recommendation A95–10. The TSB considers that TC‘s response indicates a satisfactory intent.

The risk of CFIT accidents is even greater for small aircraft, which venture further into remote, wild or mountainous terrain, but are not required to have the same ground proximity warning equipment as large airliners.

In its report on the circumstances surrounding the crash of a Beechcraft C99 Airliner in Moosonee, Ontario, on 30 April 1990, 30 the TSB noted with concern that, between 1976 and 1990, there were 170 CFIT accidents, with 152 fatalities, involving Canadian–registered, commercially operated small aircraft. In that same report, TSB indicated that, since GPWS became mandatory equipment on larger passenger-carrying aircraft, the number of CFIT accidents has decreased markedly for these aircraft. However, smaller aircraft do not require this type of warning equipment.

This safety issue is on the TSB‘s Watchlist and the TSB continues to be very concerned that, until the changes to regulations are put into effect, the deficiency will persist.

1.7.6 TSB Laboratory Examination and Analysis

C–GPBA was not equipped with a flight data recorder (FDR), nor was this required by regulation. Consequently, little data were available to establish the condition and flight path of the aircraft before the accident. The wreckage was transported to the TSB Laboratory for more detailed examination to establish its condition at the time of the accident.

1.7.6.1 Engines and Propellers

An examination of the engines determined that the integrity of the engine and propeller controls had been maintained. Teardown of the engines revealed no anomalies, other than the internal rub marks and deformation consistent with engines producing power at the time of impact.

Examination of the propellers did not reveal any pre–impact, mechanical anomalies. In addition, the observed marks and damage confirm that the propellers were in a positive angle and receiving power from the engines at impact.

1.7.6.2 Flight Controls and Landing Gear

A detailed examination of the controls, surfaces, cables and pulleys confirmed the integrity of the flight controls. No anomaly, condition or defect affecting the operation of the flight controls was observed. Examination of the flap actuators confirmed that they were working properly and that the flaps were in the approach position at the time of impact.

The nose wheel and left gear were severed and detached from the fuselage. Examination of the actuators revealed that the landing gear was down with all wheels extended at impact.

1.7.6.3 Instruments, Lights and Annunciator Panel

In March 2009, the aircraft’s pitot–static system along with the 2 altimeters were inspected and certified. No anomalies were recorded in the log book following certification. At the accident site, the 2 altimeters showed an altimeter setting of 29.34 and 29.35 inches of mercury. Microscopic examination of the altimeter faces and internal mechanisms did not provide any reliable information on altimeter indications upon impact.

Examination of the radio altimeter established that the “DH” alert light associated with the decision height was illuminated at the time of impact. It was, therefore, receiving electrical power and working normally.

The light bulbs used in the various annunciator panels were examined to determine which ones were illuminated upon impact with the ground. The GPS annunciator lights indicated that both were in approach mode, with no caution annunciator lights on. The autopilot panel lights were all out. The annunciator lights for the left and right generators and for fault warning were illuminated.

The landing lights were destroyed on impact. Examination of the landing light switches could not determine whether they were in the ON position at impact.

The screens of the 2 GPS units were shattered and the casings dented by the impact. The data cards were removed and it was determined that the database was valid until 17 December 2009; the approach fixes at Saint–Honoré were consistent with the RNAV (GNSS) instrument approach chart for Runway 12 in CAP. The 2 Garmin GPS models do not record flight path data making it impossible to determine precisely the aircraft’s track once it left radar coverage.

1.7.6.4 Seats

An examination of the seats, anchors and tracks determined that their rated load had been exceeded during impact, which explains why 6 of the 8 passenger seats became detached.

1.8 Aerodrome Information

1.8.1 General

The CYRC airport is located in the municipality of Saint–Honoré de Chicoutimi and is operated by the Quebec Department of Transport. CYRC is a registered aerodrome, but its certification is no longer required under paragraph 302.01(1)(c) of the CARs.

The Saint–Honoré control tower is closed between 2030 and 0800. During this period, control services are not available and the tower’s frequency is designated as the ATF frequency. As a result, no advisory service is available for commercial and private flights operating outside the control tower’s hours of operation.

1.8.2 Aircraft Rescue and Firefighting Service

CYRC is not equipped with aircraft rescue and firefighting (ARFF) services, nor are they required by regulation. In the event of an emergency, the fire department in the municipality of Saint–Honoré, located a few kilometres away, can be at the airport in less than 6 minutes when called by tower personnel. However, when the control tower is closed, there is no one designated to report an accident to the Saint–Honoré fire department.

1.8.3 Runway and Approach Lights/Runway Lights

CYRC has 3 asphalt runways, including Runway 12/30, which measures 6087 feet long by 150 feet wide. The touchdown zone elevation (TDZE) 31 of Runway 12 is 537 feet asl. The airport is equipped with a type K aircraft radio control of aerodrome lighting (ARCAL) system, which enables all the runway lights to be activated for approximately 15 minutes at maximum intensity by pressing a microphone button 7 times on tower frequency 118.4 MHz. Runway 12 is equipped with centre line low-intensity (AD) approach lights, threshold lights, variable medium-intensity runway edge lights (3 settings), and a 2–bar visual approach slope indicator system (VASIS).

1.8.4 Runway Conditions

The CARs 32 state that “No person shall terminate an instrument approach with a landing unless, immediately before landing, the pilot–in–command ascertains, by means of radio communication or visual inspection:“

  1. “the condition of the runway or surface of intended landing;“ and
  2. “the wind direction and speed.“

According to the aeronautical information manual (AIM), 33 “aircraft movement surface condition reports (AMSCR) are issued to alert pilots of natural surface contaminants, such as snow, ice or slush that could affect aircraft braking performance.“

Further, a NOTAM is issued on the AFTN network 34 when there is loose snow on the runway exceeding 0.25 inches in depth. All of this information is available as an advisory from an airport control tower or a flight service station (FSS) at uncontrolled aerodromes.

The final runway inspection at CYRC is usually conducted at approximately 1630, just before the departure of airport personnel. Afterwards, it is up to the pilot or the operator to contact those in charge of clearing the runway to ensure that it has been cleared. Airport personnel occasionally contact the operator to check whether any arrivals are planned for CYRC after the tower is closed.

On the day of the occurrence flight, the runway was inspected at 1625. Due to heavy snowfall and strong winds, the personnel in charge of clearing the runway returned to the airport at about 2210 for an additional check. There was no snow accumulation on Runway 12 at that time. Once the tower is closed, the frequency becomes an ATF rather than a mandatory frequency (MF). As such, no advisory service is available and there is no mechanism in place at CYRC to receive and then transmit observed runway conditions.

At 2215, the crew attempted to obtain runway condition information at CYRC from the Québec FIC before landing. Because the CYRC tower was closed, the FIC could not obtain an update on runway conditions and the latest available for CYRC had been issued at 1625, nearly 6 hours earlier.

The TSB Watchlist, released in March 2010, also addresses the risks of runway overruns and the importance of having accurate reports of runway surface conditions made available to pilots. The Air fact sheet, published by the TSB in conjunction with the Watchlist, points out that “more must be done to ensure safe landings” and that “in bad weather, pilots need to receive timely information about runway surface conditions.”

1.8.5 Communications

The CARs 35 state that the pilot–in–command of an IFR aircraft who intends to conduct an approach to or a landing at an uncontrolled aerodrome shall report intentions regarding the operation of the aircraft:

  • Five minutes before the estimated time of commencing the approach procedure, stating the estimated time of landing
  • When commencing a circling manoeuvre
  • As soon as practicable after initiating a missed approach procedure

The pilot–in–command shall also report the aircraft’s position:

  • When passing the fix outbound, where the pilot–in–command intends to conduct a procedure turn or, if no procedure turn is intended, when the aircraft first intercepts the final approach course
  • When passing the final approach fix or 3 minutes before the estimated time of landing where no final approach fix exists
  • On final approach

Omission of position reports is a systemic phenomenon previously identified by the TSB in 2007. 37

The Civil aviation daily occurrence reporting system (CADORS) contains many occurrence reports pertaining to non-compliance with mandatory frequency (MF) area communication procedures in Canada. For 2008 and 2009, CADORS contained 118 occurrence reports of non–compliance. Occurrences linked with ATF areas are rarely reported because the CARs do not require compliance with VFR communications procedures at uncontrolled aerodromes within an ATF area. However, the AIM states that these IFR reporting procedures “should also be followed by the pilot–in-–command at aerodromes with an ATF.”

The crew communicated its position only once on frequency 118.4 MHz, “[Translation] approaching RABAD, soon final for Runway 12,” at 2248:53. However, the position recorded by Bagotville radar at that precise moment corresponded to 0.4 nm before the FAF (ESRIX), i.e. 4.6 nm after crossing RABAD.

In light of this positional discrepancy, research was carried out by the TSB Laboratory to check the validity of the times recorded by the tower and by Bagotville radar. It was determined that the 2 recorders were using a common time source, i.e. GPS network time. The tower frequency recorded time was then compared with the time signal broadcast by the National Research Council, and the difference was 0.3 of a second.

The recording on frequency 118.4 MHz revealed a first series of 8 clicks starting at 2251:42, which, via the ARCAL system, activated all airport lighting including the approach lights for Runway 12. This series of clicks was followed by several additional series of clicks ending at 2252:44. However, as the crash occurred at about 2250, almost 2 minutes before the first series of clicks was recorded, the crew did not initiate the aerodrome lighting start–up sequence. As a result, the airport lights, approach lights and VASIS were not illuminated at the time of the accident.

There were no other aircraft in the air or on the ground in the Saint–Honoré area when the ARCAL system was activated, and the investigation was unable to determine the source of these transmissions. The TSB conducted a sound analysis to verify the origin of the transmissions producing the clicks. A comparison of the sonograms associated with the various recorded transmissions confirmed that C–GPBA was not the source of the transmissions producing the clicks that occurred after 2251.

1.9 Tests and Research

On 02 March 2010, the TSB conducted a series of test flights at CYRC airport to evaluate the RNAV (GNSS) Runway 12 approach. The first flight was conducted using an aircraft equipped with an FMS that charted an optimum descent path of 3°. The FMS calculated the fix crossing altitude for RABAD as 3757 feet asl, for ESRIX as 2169 feet asl, and for OTUTI as 1532 feet asl, approaching the runway threshold at 581 feet asl, or 44 feet above the surface of the runway.

The aim of the second flight, conducted at night, was to re–enact the occurrence approach. A BE10 from the company equipped with the same GPS models as C–GPBA was used for this purpose. The first RNAV (GNSS) Runway 12 approach began at the XESUT fix, flying the same descent profile as C–GPBA to the FAF crossing altitude, then descending to the minimum altitude before OTUTI. The second approach was flown using a step–down descent, tracking the altitudes published in CAP from XESUT to MDA.

The test flights established that, when a step–down approach is flown at the altitudes published in CAP, the aircraft is at minimum altitude, far from the runway threshold. The descent path from the FAF to the runway is shallow and significantly lower than the 3° optimum descent angle. As a result, the aircraft remained at the minimum obstacle clearance altitudes, near the ground, for longer periods than most of the other approaches flown by this crew.

The night flight revealed the presence of light sources along the approach path, i.e. the lights at a mine located approximately 4 nm from the threshold of Runway 12 and the lights of a service station located one nm from the threshold. However, the absence of lights in the vicinity of the accident site was also noted. According to available information, the intensity of the lights at the mine has increased significantly over the past few years.

Figure 2. Satellite mosaic with lights on approach
Figure 2. Satellite mosaic with lights on approach ↑

The TSB Laboratory created a composite image of the final approach by superimposing the light sources over a satellite mosaic image (Figure 2). The image shows the estimated position of the aircraft at MDA, relative to the cluster of lights at the mine and the service station.

The black hole effect is an illusion that occurs when an aircraft is on a night approach over unlit terrain. When an aircraft is on approach to a landing area and all is dark below the approach path with only the distant lights providing visual stimuli, an illusory or false sense of height may be perceived. 38 The pilot believes the aircraft to be higher than it actually is, which then causes the pilot to execute the approach lower than the desired approach path, thereby increasing CFIT risk.

1.10 Instrument Approach Information

1.10.1 General

NAV CANADA responsibilities include providing aeronautical information services (AIS) in Canada to meet the requirements of annexes 4 and 15 to the Convention on International Civil Aviation (Convention). 39 NAV CANADA is, therefore, responsible for the design, depiction and publication of instrument approach charts in Canada. Other organizations, such as Navtech, Jeppesen and Lido, can also provide aeronautical information services, including instrument approach charts, provided the information has already been distributed by NAV CANADA.

Annex 4 of the Convention describes the specifications for aeronautical charts and constitutes the international standards and recommended practices, which are defined as follows:

  • Standard: “Any specification… the uniform application of which is recognized as necessary for the safety…”
  • Recommended Practice: “Any specification… the uniform application of which is recognized as desirable in the interests of safety…”

1.10.2 Regulatory Overview

TC ensures regulatory overview of activities relating to the provision of aeronautical information services in Canada, including the design and depiction of instrument approaches.

Canada is a member state of ICAO. The CARs 40 state that aeronautical information services must be in accordance with the standards set out in annexes   and 15 of the Convention. However, the CARs do not require compliance with the recommended practices in the Convention annexes.

1.10.3 Instrument Approach Design

Instrument approach procedures in Canada are developed based on a TC manual, entitled Criteria for the Development of Instrument Procedures (TP308/GPH209). According to TP308, “obstacle clearance is the primary safety consideration in the development of instrument procedures.“

TP308 states that the optimum descent path for a non-precision final approach segment is 318 feet per nm, or an angle of 3°, and its use is recommended.

The FAF altitude published in the CAP for the RNAV (GNSS) Runway 12 approach chart at CYRC is 1300 feet asl and this corresponds to a minimum obstacle clearance altitude. Using a height of 46 feet to cross the runway threshold, the resulting descent angle is 1.35°. According to the calculations in TP308 used to determine the FAF crossing altitude on an optimum path of 3°, this would produce an altitude of 2173 feet asl at the FAF. However, this calculated altitude does not appear on the approach charts published in the CAP.

TP308 does not include any specifications for creating tables to cross–check distance versus altitude as presented in altitude/distance tables, to help pilots follow an optimum descent angle of 3° on non-precision approaches. Consequently, no altitude/distance table appears on the CAP approach charts.

1.10.4 Instrument Approach Depiction

The depiction of instrument approaches in the CAP is based on NAV CANADA specifications, which in turn must comply with the standards outlined in Annex 4.

According to the standards in Annex 4, the RNAV (GNSS) Runway 12 approach chart at CYRC, published in the CAP, must indicate the descent angle in the approach profile view. 41 In 2000, TC issued a finding of non-compliance following an audit of NAV CANADA activities, because the angle of descent did not appear on the approach charts published in the CAP. In 2004, TC issued a reminder because no corrective action had yet been taken. At that point, NAV CANADA asked TC to file a difference with ICAO on this non-compliance with the standard in Annex 4. Consequently, the descent angles are still not indicated on the non precision approach charts published in the CAP.

According to the recommended practices in Annex 4, the chart should include a rate of descent table 42, and the profile view should include a terrain profile or a depiction of minimum altitudes, using either a continuous line to represent the terrain profile or shaded blocks indicating the minimum altitudes of the intermediate or final approach segments 43 (Appendix C). The RNAV (GNSS) Runway 12 approach chart at CYRC published in CAP does not incorporate, the recommended practices set out in Annex 4 (and is not required to) on the following points:

  • The chart does not include a rate of descent table.
  • The terrain profile or the shaded blocks indicating minimum altitudes are not depicted.

Figure 3. Descent profile published in the Canada Air Pilot
Figure 3. Descent profile published in the CAP ↑

In December 2009, there were 1339 instrument approaches in Canada, 1217 of which were non–precision approaches (91% of the total).

1.11 Instrument Approach Techniques

1.11.1 General

There are essentially 2 techniques for completing the final descent on a non–precision approach: step–down descent and final descent on a stabilized constant descent angle (SCDA).

1.11.2 Step–down Descent

The step–down descent technique involves flying an aircraft down to the published minimum IFR altitudes or MDA and levelling off. The obstacle clearance may be as low as 250 feet agl. The result is an extended flight at low altitude, waiting either to obtain the visual references needed to continue the descent until the runway or to reach the missed approach point. Consequently, aircraft spend more time than necessary at altitudes that provide a minimum obstacle clearance, thereby increasing the risk of CFIT accidents.

This type of descent increases pilot workload because the successive descents and level-offs require significant changes in attitude and power to maintain a constant speed. The tasks performed while completing these manoeuvres are knowledge–based, 44 requiring more cognitive effort on the part of the PF and depend on the use of prospective memory. Prospective memory is the memory used to remember that a task must be performed in the near future. Unfortunately, it is known for its limited reliability. Whenever there is a delay between the planning of a task and its execution, such as during periods of heavy workload, or when distractions arise, there is a risk the task will not be completed. 45 Therefore, to perform tasks that have a significant impact on fight safety, the usual approach is to organize these tasks by means of standardized procedures to avoid depending solely on prospective memory. 46

In the case of an aircraft equipped with a traditional cockpit, such as C–GPBA, the crew needs to interpret information for the purpose of carrying out and monitoring these manoeuvres. Instruments that are less intuitive to read, and often not as well illuminated as the latest generation of LCD instruments, require an additional cognitive effort.

During the RNAV (GNSS) Runway 12 approach at CYRC, the crew used the step-down descent technique (Figure 4). After passing RABAD at 10 nm on final, a rate of descent of approximately 1700 feet per minute was used to reach the CAP-published altitude of 1300 feet asl for the ESRIX FAF. According to the radar data, the aircraft passed ESRIX at 1100 feet, began its descent 0.4 nm past ESRIX with a groundspeed of 100 knots. The initial point of impact with the treetops occurred at an altitude of approximately 500 feet asl, at a distance of 1.6 nm from the last radar position. Based on the last ground speed recorded by radar, it took 58 seconds to cover this distance, which translates into an average rate of descent of 600 feet per minute.

Figure 4. Step-down descent used by C-GPBA crew
Figure 4. Descent profile published in the CAP ↑

1.11.3 Stabilized Constant Descent Angle

The SCDA technique involves intercepting and maintaining an optimum descent angle of 3° to MDA, which is used as a decision altitude. The descent is therefore flown at a constant angle and constant rate of descent, requiring no configuration change. At MDA, the aircraft does not level off. Therefore, at that moment, either the required visual references are available to continue the approach and land, or a missed approach is initiated. The execution of this type of descent consists primarily of controlling the rate of descent, which calls upon skill-based tasks 47 and reduces the cognitive effort, consequently the workload. 48 These tasks associated with an SCDA descent use less prospective memory.

1.11.3.1 Airbus

Airbus technical documentation on non–precision approaches recommends the use of SCDA rather than the classic step-down descent technique, because SCDA results in a stable approach that reduces crew workload during a critical phase of the flight and, therefore, reduces the risks of a CFIT accident.

1.11.3.2 Boeing

According to Boeing, SCDAs can be performed on all non–precision approaches. They can increase safety, prevent CFIT accidents and improve operational capacity. The flight crew training manuals (FCTM) include general information on the use of a constant descent to perform non precision approaches, whereas the various aircraft flight crew operating manuals (FCOM) detail the procedure for performing these approaches on each type of aircraft.

1.11.3.3 National Transportation Safety Board

Following an accident in November 1995 involving a collision with trees on approach, the National Transportation Safety Board (NTSB) issued a recommendation in November 1996 aimed at incorporating a constant angle of descent rather than step–down descents into the U.S. design Standard of the Terminal Instrument Procedures (TERPS) 49 governing non–precision approaches. In 2008, after several other accidents, the NTSB issued a recommendation to mandate commercial operators to use the SCDA descent technique for non–precision approaches.

1.11.3.4 U.S. Federal Aviation Administration

In 2004, the FAA incorporated a constant angle of descent in about 90 non–precision approaches at airports that serve commercial carriers. The remaining airports were scheduled to have constant angle of descent approach information added by September 2007. 50 Furthermore, the FAA has endorsed the use of the constant descent angle technique in several publications, 51 including its Airplane Flying Handbook52 The handbook states, in part, that the SCDA procedure facilitates stabilized descents for non–precision approaches.

In January 2011, the FAA issued a circular 53 addressing the need to use the SCDA descent technique, along with its advantages, and explained how it could be implemented through SOPs and crew training.

1.11.3.5 Japan

In 2006, Japan introduced the use of constant descent angle profiles with shaded minima for each segment, on its approach charts in compliance with the recommendations of Annex 4.

Figure 5. Descent profile used in Japan
Figure 5. Descent profile used in Japan ↑

1.11.3.6 European Union (EU)

In August 2008, the European Commission amended the regulation concerning aerodrome operating minima (EU-OPS1), 54 which replaced the JAR OPS1 regulation in July 2008. Among other things, this change requires all approaches be flown as stabilized approaches 55 and that the continuous descent final approach (CDFA) technique, 56 which is equivalent to SCDA, be used for all standard non–precision approaches. Therefore, all European Union operators were required to use this approach technique by 16 July 2011 at the latest.

According to Jeppesen, an AIS Provider, changes to the design and depiction of instrument approach procedures were completed by 16 July 2011 for most approaches on the territory of the European Union 57 to be compliant with the new EU–OPS1 standards. As of early 2012, 31 smaller airports still have not had their approach procedures updated to the new design and depiction standard.

The charts produced by Jeppesen incorporate non–precision approach profiles consistent with the standards and recommendations of Annex 4 (Figure 6). These charts will help European Union operators comply with the EU–OPS1 standards by clearly depicting the path to be followed (designed to be 3°). This 3° angle facilitates stabilized descents, similar to precision approaches. The recommended altitudes for flying this descent path, combined with an altitude/distance table and a rate of descent table, make it easier to monitor the descent on approach. Lastly, the shaded blocks indicate minimum obstacle clearance altitudes, providing awareness of the height of the path above terrain.

Figure 6. Descent profile used on European Union approach charts (Jeppesen).
Figure 6. Descent profile used on European Union approach charts (Jeppesen). ↑

1.12 Controlled Flight into Terrain

CFIT occurs when an airworthy aircraft under the control of the pilot is inadvertently flown into the ground, water or obstacle. In these occurrences, pilots are unaware of the danger until it is too late. This type of accident often happens when visibility is low, at night or during poor weather. Such conditions reduce a pilot’s situational awareness and make it difficult to tell whether the aircraft is too close to the ground.

According to the Flight Safety Foundation (FSF), in the early 1980s, CFIT accidents were the leading cause of aviation fatalities. A task force was created in 1992 with the mandate to reduce the number of CFIT accidents. Spearheaded by the FSF, the task force was set up with over 150 representatives from the airlines, aircraft and equipment manufacturers, as well as technical, research and professional organizations. The task force believed that education and training were easily accessible tools to help prevent CFIT accidents.

In March 2010, the TSB released its Watchlist identifying the safety issues investigated by the TSB that pose the greatest risk to Canadians. In each case, actions taken to date are inadequate and concrete steps must be taken on the part of industry and the regulator to eliminate these risks. One of the safety issues identified in TSB‘s Watchlist was CFIT accidents.

Counting all types of operations and aircraft, there were 129 CFIT accidents in Canada 58 and 128 fatalities between 2000 and 2009. CFIT accidents account for 5% of accidents, but nearly 25% of all fatalities. Considering only aircraft registered in Canada for air taxi service, there were 26 CFIT accidents over the same period of time, resulting in 42 fatalities. Furthermore, for air taxi operators, these accidents accounted for 7% of total accidents, but 35% of fatalities during this 10–year period.

1.13 Approach and Landing Accidents

1.13.1 General

A second phase in the CFIT accident reduction program was the creation, in 1996, of the Flight Safety Foundation (FSF) Approach–and–Landing Accident Reduction task force (ALAR) 59. By focusing on approach and landing, the task force was able to work outside the strict definition of CFIT accidents, which does not include landing short or long, runway overruns, or loss of control following an unstable approach. Therefore, for purposes of clarity and consistency, this report will use ALA to designate approach and landing accidents, including CFIT accidents on approach.

In 1998, the FSF task force issued the following recommendations targeting the reduction and prevention of the ALA accidents.

1.13.2 Recommendations Concerning Company Policies

  • Operators should specify well–defined 60 approach gates.
  • Operators should define the parameters of a stabilized approach in their company flight operations manuals (FOM) and aircraft operating manuals (AOM).
  • The stabilized approach policy should at least cover the flight path, speed, power setting, altitude and rate of descent, as well as configuration and flight crew landing readiness.
  • All flights should be stabilized by 1000 feet agl in instrument meteorological conditions (IMC) and by 500 feet agl in visual meteorological conditions (VMC).
  • Operators should develop and support “no–fault“ go–around and missed approach policies.
  • FOMs or SOPs should require a go–around if an aircraft becomes unstable during approach.
  • Operators should implement SCDA procedures for non–precision approaches.
  • Operators should develop and implement a policy on appropriate autopilot use in conditions of reduced visibility, at night or in the presence of optical or physiological illusions.
  • Operators should establish clear directives for TAWS alerts.

1.13.3 Recommendations Concerning SOPs

  • States should mandate, and operators should develop and implement, SOPs for approach–and–landing operations.
  • States should mandate the use of SOPs for approach–and–landing operations.
  • Operators should develop SOPs for autopilot use during approaches and landings.
  • Operators should have a clear policy on the role of the pilot–in–command in complex situations and train accordingly.
  • A risk assessment checklist should be used to identify approach and landing hazards.

1.13.4 Recommendations Concerning Training

  • Crews should be trained to identify operational risks associated with adverse conditions, such as reduced visibility, visual illusions, contaminated runways and cross winds.
  • The training should deal with non precision approaches, especially those that involve shallow approach paths or stepped descents.
  • Crews should be trained to take the time to implement corrective actions when the cockpit situation becomes confusing, ambiguous or task saturated.
  • Operators should develop and implement a policy on appropriate autopilot use along with navigation aids for the approaches being flown.
  • Crews should receive training on SCDA approach procedures.
  • Crews should be educated about approach design criteria and minimum obstacle clearance requirements.

1.13.5 Recommendations Concerning Decision Making

  • Operators should provide education and training that enhance decision making and risk (error) management.
  • Operators should develop a decision–making model for use in time–critical situations (where the time available for decision making is limited).
  • Provide improved training on error management and risk assessment as well as on mitigating the consequences of errors.

1.13.6 Recommendations Concerning CVRs and FDRs

  • Regulatory authorities should encourage the installation of FDRs and CVRs on aircraft for which they are currently not required.

1.13.7 Recommendations Concerning Autopilot

  • The FSF task force recommended that the autopilot be used, especially in conditions of reduced visibility, at night or in the presence of optical or physiological illusions.

1.13.8 Recommendations Concerning Radio Altimeter

  • Operators should state that the radio altimeter is to be used during approach operations and specify procedures for its use.
  • Train crews to correct the radio altimeter bug to 200 feet agl on all approaches except for CAT II and III.
  • Train crews to initiate an aggressive go–around if the alarm sounds without visual contact being established with the runway.
  • Operators should activate automatic callouts or require callouts from their crews, at 2500, 1000 and 500 feet agl as well as at the minimums.

Other than Exact Air’s publication of an SOP and the provision of training for takeoffs and landings in cross–winds and on contaminated runways, none of the other FSF task force recommendations had been implemented at the time of the occurrence. It should be noted that most air taxi operators do not implement these recommendations, nor are they required to do so by regulation.

1.13.9 Recommendations Concerning Instrument Approach Procedure Design

  • Non–precision approach procedures should be constructed, whenever possible, in accordance with established stabilized approach criteria.
  • The final approach glide path should be a nominal 3° where terrain permits.
  • A continuous descent is preferred to a stepped approach.

1.13.10 Recommendations Concerning the Depiction of Instrument Approach Charts

  • Non–precision approach charts should show the descent profile to be flown instead of the minimum obstacle clearance altitudes.

None of the FSF task force recommendations concerning the design and depiction of instrument approaches was incorporated into the RNAV (GNSS) Runway 12 approach at CYRC published in the CAP (Appendix A), nor are they required by regulation.

1.13.11 Recommendations Concerning the SCDA Approach Technique

  • Implement use of SCDA procedure for non–precision approaches.
  • Crews should receive training on SCDA approach procedures.
  • Crews should be educated on approach design criteria and minimum obstacle clearance requirements.

The FSF task force found that the accident risk during a non–precision approach was 5 times greater than during a precision approach and it recognized the need for stabilized approaches. However, the stabilized approach is not formally used by air taxi operators in Canada, nor is it required by regulation.

1.13.12 FSF ALAR Tool Kit

Further to the recommendations of the FSF task force, an ALAR tool kit was developed and distributed by the FSF as a resource that could be modified as required and used for training pilots, air traffic controllers and managers. The tool kit contains the report of the ALAR task force, conclusions and recommendations, videos, presentations, hazard checklists, documentary notes and, lastly, other products designed to prevent approach and landing accidents.

The International Air Transport Association (IATA) has endorsed the FSF ALAR Tool Kit and has recommended that its members use it. In 2001, ICAO stated that the ALAR Tool Kit contained extremely valid accident prevention information and that member states should consider incorporating the material into their training programs. ICAO then purchased and distributed 10 000 copies of the tool kit at its 33rd Assembly in the fall of 2001. To date, approximately 40 000 copies of the tool kit have been distributed worldwide. At the time of the accident, Exact Air Inc., like the majority of air taxi operators, was unaware of the existence of the FSF ALAR Tool Kit.

1.13.13 Other Approach and Landing Accident Reduction Initiatives

Among the teams mandated by the FAA were the GA CFIT Joint Safety Analysis Team (JSAT), which was asked to study CFIT accidents, and the CFIT Joint Safety Implementation Team (JSIT), charged with implementing the intervention strategies proposed by JSAT. In March 2003, the FAA released a study on general aviation CFIT accidents 61 that validated the efforts of JSAT and JSIT.

The National Lucht–en Ruimtevaartlaboratorium in the Netherlands published a CFIT report in 1997, 62 which stated that 70% of CFIT accidents occurred during approach and landing, and further that 95% of these accidents involved regional carriers. Among other things, the report recommended the installation of ground proximity warning devices and use of the FSF Tool Kit.

In 2007, the ATSB published a research and analysis report on CFIT accidents in Australia. 63 It concluded that, despite international efforts, CFITs continued to be a challenge. In addition, the report stated that a sustained effort was justified to reduce the risk of CFIT accidents, given the strong likelihood of such occurrences resulting in loss of life.

In 1998, TC published an article titled “CFIT – Why Are Aircraft Flying at Minimum IFR Altitudes?” 64 After reviewing the FSF Tool Kit, the author emphasized that the kit should be “required reading for ALL pilots who are currently flying in the world’s skies”. The article acknowledged that most CFIT events occurred on non–precision approaches and while discussing minimum IFR altitudes on approach he asks, “why are you there ?”. The answer can be found in part within the same article — “because that’s what is published.” The article then reminds pilots that the altitudes published on instrument approach charts are minimum obstacle clearances altitudes and not necessarily target altitudes. TC reprinted the same article in the first 2011 issue of the Aviation Safety Letter, pointing out that it is still relevant 13 years later.

In 1999, TC published an Air Carrier Advisory Circular (ACAC) 65 intended to bring to the attention of air carriers the soon to be implemented CARs requirements for mandatory training for CFIT accident avoidance. The circular cited the FSF Tool Kit as a reference and encouraged carriers to use it in developing adequate CFIT training.

In September 2006, TC published a Commercial and Business Aviation Advisory Circular (CBAAC) pertaining to changes to the Approach Ban that were to come into force on 01 December 2006. 66 The CBAAC was aimed primarily at commercial operators governed by sections 703, 704 and 705 of the CARs and who wanted to benefit from reduced approach ban visibility values. The CBAAC acknowledged the work done by the FSF task force and the need to carefully control an aircraft’s vertical position on approach. The risks associated with step–down descents were explained and the SCDA technique introduced as a way to prevent CFIT accidents.

However, neither the Instrument Procedures Manual (TP2076) nor the Aeronautical Information Manual (TP14371) published by TC explains the use of the SCDA technique. NAV CANADA does not distribute information on this technique, since the approaches published in the CAP are not designed based on SCDA descents. In addition, even if pilots wanted to use this technique, the instrument approach charts published in the CAP do not display the optimum 3° decent path to be flown.

None of the pilots interviewed during this investigation were familiar with the SCDA technique.

1.13.14 Approach and Landing Accidents in Canada

According to data compiled by the TSB, the ALA rate for commercial operations seems to have generally decreased only slightly over the past decade whereas the number of fatalities has remained constant. Between 2000 and 2009, ALAs accounted for 62% of all accidents involving air taxi services in Canada. 67 The number of accidents involving air taxi operations is still considerably higher than the number of accidents for airline and commuter operations, accounting for approximately 70% of all commercial operation ALAs. The result is that, on average, there are 12 times more ALAs in air taxi service than in airline operations.

Figure 7. Number of commercial operation approach and landing accidents in Canada involving Canadian-registered aircraft
Figure 7. Number of commercial operation ALAs in Canada involving Canadian–registered aircraft ↑

Approximately 80% of commercial operation ALAs have taken place at airports that are only equipped with non–precision instrument approaches. Regional airports, which are rarely equipped for precision instrument approaches, are generally those used by air taxi operators.

Between 2008 and 2009, including this accident, the following ALAs and occurrences were investigated by the TSB 68 and all occurred following a non–precision approach:

  • A Dornier 228 collided with the ground 1.5 nm before the runway threshold, on 13 December 2008;
  • A Boeing 727 struck some trees 2.7 nm before the runway threshold, on 19 February 2008;
  • A DH8 overran the runway on 14 December 2008;
  • A BE10 struck some trees 2.5 nm before the runway threshold, on 16 January 2009;
  • A BE10 struck some trees 3.0 nm before the runway threshold, on 09 December 2009.

Following these investigations, the TSB reports noted in several instances the importance of the FSF ALAR task force’s recommendations in reducing the risks of ALA accidents.

1.14 ICAO Risk Assessment Matrix

ICAO defines risk as “the assessment, expressed in terms of predicted probability and severity, of the consequences of a hazard, taking as reference the worst foreseeable situation.” 69 When the probability is considered to be remote and the severity, catastrophic, ICAO‘s risk tolerability matrix (Appendix D) shows that the risk is unacceptable and strategies to control or mitigate the risks must be put in place.

The following TSB laboratory reports were completed:

LP172/2009 – Continuity Determination LP174/2009 – Instrument Examination LP175/2009 – Engine Examination LP021/2010 – Sound Analysis LP042/2010 – Investigation Diagrams LP064/2010 – Seat Examination LP180/2010 – ELTExamination

These reports are available from the Transportation Safety Board of Canada upon request.

2.0 Analysis

The crew performed a non–precision approach at night in adverse weather conditions. The aircraft was in controlled flight when it descended below MDA and struck treetops 3 nautical miles (nm) from the runway threshold. A detailed examination of the wreckage and its components did not indicate any failure that contributed to the accident.

Consequently, the analysis will focus initially on the circumstances of the flight and the factors that could have led the pilots to descend prematurely below MDA, apparently without realizing the proximity of the terrain. The analysis will then look at Approach and Landing Accident (ALA) risks along with proven mitigation strategies.

2.1 The Flight

Before taking off from Val–d’Or (CYVO), the crew was aware of the forecast conditions at Bagotville (CYBG). These conditions did not meet CARs requirements for an alternate airport. Given that no METAR was available for CYRC airport, the crew could not know the prevailing conditions at the destination. However, given the proximity of CYBG airport to CYRC, the crew could have expected similar conditions. Moreover, given the adverse weather conditions at the destination airport, it was important that the selected alternate airport provide an alternative landing option in the event of a diversion. Nevertheless, the crew did not change the designated alternate airport on the flight plan despite having sufficient fuel for 1 hour and 52 minutes of extra flight time. As the flight is operated under a self–dispatch operational control system, the captain is solely responsible for filing the operational flight plan, which includes the alternate airport selection.

During the flight, the crew tried to obtain the latest runway conditions from the Québec City FIC; but, because the CYRC tower was closed, the information was not available. Millions of landings take place every year on runways in Canada. Rain, snow, ice and melting snow can contaminate runways and have an impact on the landing distance. Pilots must calculate the landing distance before each attempt. To this end, they require accurate information on the condition of the runway surface. If such information is not available, the landing distance could be miscalculated and a runway excursion could occur.

Before attempting the approach and landing at CYRC, the PNF should have indicated the crew’s intention on the ATF frequency at least 5 minutes before initiating the approach. Position reports were required at RABAD and then at the FAF. However, only one call was made from C–GPBA, just before crossing the FAF. Omitting to report an aircraft’s position is a recurring phenomenon. However, it is essential for flight safety in uncontrolled airspace that pilots follow established procedures to avoid conflicts with other aircraft and vehicles on the ground.

The Canadian Mission Control Centre (CMCC) in Trenton was advised that C–GPBA’s ELT had activated, but the Canadian Beacon Registry did not have any owner information in case of an emergency. Because this was a commercial operator, additional research made it possible to locate the company’s managers. In other circumstances, however, the delay could be longer and have serious repercussions for survivors. Consequently, it is essential that ELTs also be registered with the Canadian Beacon Registry so that the owner or operator of an aircraft can be quickly contacted.

Cell phones are ubiquitous and are more and more used to report accidents. During search and rescue efforts, the location of the passenger’s call to 911 emergency services was established 5 nm to the southeast of the accident site. This position gap increased search time, which increased the risk of additional suffering and loss of life.

2.2 Descent below MDA

2.2.1 General

The copilot was the pilot flying (PF) and in preparing for the approach should normally have completed an approach briefing as per SOPs, which includes a briefing on the approach chart and published minimum altitudes. Normally, a crew would apply an altimeter correction for low temperature to the CAP published altitudes.

As the aircraft was flying at a higher altitude and speed than normal on its initial approach, it is possible that the crew’s workload was high at the beginning of the approach. The aircraft intercepted the final approach course at 3900 feet asl with a ground speed of 200 knots. A rate of descent of approximately 1700 feet per minute was used to reach the CAP published altitude of 1300 feet asl before crossing the FAF.

The crew made its first call on the ATF frequency just before crossing the FAF, but indicated that it was approaching RABAD instead of the ESRIX FAF. Omission of the other required calls and the position error may have been caused by the crew’s heavy workload.

Based on the radar data, the aircraft crossed the FAF at 1100 feet asl, 200 feet below the published altitude. The crew would normally have applied the altimeter correction of 67 feet for low temperature and the correction of 30 feet for use of the CYBG altimeter setting to ensure they would cross the FAF at 1300 feet asl. These altimeter corrections are important because the crew was targeting the CAP published altitude, which is, in fact, a minimum obstacle clearance altitude. When an aircraft descends below the published altitude, safety margins are reduced and the aircraft is at risk of a CFIT accident.

Because the step–down descent technique was used, the PF needed to manoeuvre the aircraft to reach the FAF at the CAP published altitude of 1300 feet asl (corrected to 1397 feet asl), with flaps in the approach position and the landing gear down, maintaining an indicated approach speed of approximately 130 knots. After crossing the FAF, the PF was to descend and maintain an altitude of 900 feet asl (altitude corrected to 970 feet asl) until the OTUTI step–down fix, then descend to the MDA of 860 feet asl (corrected to 920 feet asl).

The step–down descent placed the aircraft at the MDA at a distance of approximately 4 nm from the runway threshold. Consequently, the PF had to stop the descent and maintain MDA until the required visual references could be acquired, before continuing the descent to the runway. To follow an optimum 3° path from MDA to the runway, the descent needed to be initiated less than 1 nm from the runway threshold. Therefore, the aircraft had to remain level at MDA for approximately 3 nm, which at a ground speed of 100 knots would take 1 minute and 48 seconds.

When the aircraft left radar coverage at 1100 feet asl, its location was 0.5 nm past the FAF. Once the descent was initiated, the PNF had to call out “100 to go” and the PF had to stop the descent at 970 feet asl, which corresponds to a height of approximately 450 feet agl. Based on an elapsed time of 57 seconds between the last radar position and the point of impact with the treetops, the average rate of descent was 600 feet per minute. This would mean the crew used the usual rate of descent to reach the MDA, without levelling off at minimums.

In the absence of a CVR, it was not possible to determine:

  • The events in the cockpit during the approach
  • The crew’s workload
  • The CRM‘s effectiveness
  • Whether the altimeter corrections for low temperature and remote altimeter setting were calculated and applied
  • Whether the checklist was completed
  • The reason why the aircraft descended below the published FAF crossing altitude followed by the descent below the MDA

TC‘s intent is to ensure that a CVR be installed when a multi–engine turbine–powered aircraft has 6 or more seats and 2 pilots are required either by the aircraft type certificate or by the subpart under which the aircraft is operated. Following the judgment of the Federal Court of Appeal, TC is still in the process of clarifying the requirement for a CVR in 2 pilot operations.

2.2.2 Factors, Influences and Scenarios

2.2.2.1 Autopilot

The use of an autopilot is recommended by several organizations as a way to reduce pilots’ workload so they can better concentrate on acquiring the required visual references necessary before continuing the descent below MDA. C–GPBA’s autopilot was not working. Even when working, however, the autopilot is generally not used by BE10s on final approach because the means for controlling the descent are limited.

2.2.2.2 Terrain Awareness Warning System (TAWS)

C–GPBA was normally based at CYRC and was the company’s only BE10 not fitted with TAWS.

The presence of TAWS on board aircraft provides pilots with an added sense of safety and they become accustomed to it with the occasional terrain proximity warnings that appear on approach. As the occurrence aircraft descended below 300 feet agl at a distance between 3 and 4 nm from the runway, a TAWS equipped aircraft would have provided the crew with a premature descent alerting amber caution alert, with the associated “Too Low Terrain” aural message.

Additionally, when the predicted impact with the terrain was within 30 seconds, an amber caution alert with the associated “Caution Terrain; Caution Terrain” aural message would have been generated. Finally, when within 15 seconds of impact, a red warning alert with the associated “Terrain, Terrain; Pull Up, Pull Up” aural message would have been provided to the crew.

Because the crew was based at Baie–Comeau and flew almost exclusively on the BE10s equipped with TAWS, the pilots may have forgotten that C–GPBA was not equipped with one. Given their workload on approach, it is possible that the pilots expected that, were the aircraft too near the ground, the TAWS warning would have sounded. 70

The TSB has investigated numerous collisions with land and water and has identified deficiencies, made findings and issued recommendations, such as installing ground proximity warning systems. Although some action has been taken, more needs to be done. Wider use of technology is needed to help pilots assess their proximity to terrain.

In 2012, the CARs still do not require installation of ground proximity warning devices on aircraft operating in commercial air taxi service.

2.2.2.3 Altimeters

The fact that the radar recorded the aircraft at appropriate altitudes throughout the flight would seem to indicate that the altimeters were working properly. However, because the 2 barometric altimeters were not equipped with a target altitude bug, the crew had to rely on their prospective memory when it came time to level off at MDA.

The radio altimeter decision height bug was set at approximately 1500 feet (agl). Given that the ground in this area is at approximately 450 feet asl, the “DH” light illuminated when the aircraft descended below 1950 feet asl. At that moment, the aircraft was 2.6 nm before ESRIX, i.e., 7.6 nm from the threshold of Runway 12.

This reminder probably would not have elicited a response from the crew as it wasn’t linked to an approach altitude. Moreover, an adjusted setting above 1000 feet agl makes detecting ground proximity more difficult because of the calculations and interpretation required.

The FSF recommends setting the decision height bug at 200 feet agl on non–precision approaches as a means of increasing awareness on the part of crews to the proximity of the ground. At a normal rate of descent of 600 feet per minute, the “DH” light will illuminate about 20 seconds before impact with the ground. As, at this height, an aircraft on a 3° path should be at a distance of 0.6 nm from the runway threshold, the runway should be in sight directly in front of the aircraft.

Using this recommended procedure, it is possible to initiate an immediate go around without calculations or interpretations when the “DH” light illuminates and the runway is not in sight.

As the CARs do not require use of a radio altimeter for non-precision approaches, and the FSF recommendations regarding radio altimeters are not known or implemented, this additional defence against ALAs was not used.

2.2.2.4 Distraction Caused by an Emergency or Abnormal Situation

The annunciator panel lights were examined at the TSB Laboratory and it was determined that the left and right generator lights were on, as was the fault warning light. No fault warning alarm was noticed from the passenger cabin before the impact with the trees. As the aircraft traveled a distance of approximately 600 feet through the trees and the wings were severed before impact with the ground, it is reasonable to assume that the generators stopped working as a result of the collision with the trees. Consequently, it is unlikely that the descent below MDA was caused by a significant distraction related to a major electrical failure or the illumination of the fault warning.

2.2.2.5 Intentional Descent Without Visual References

It is unlikely that the crew chose deliberately to descend below MDA without having first acquired visual references, since the base of the cloud layer in the area was at 4200 feet agl . The aircraft reached MDA at a distance of approximately 4 nm from the runway threshold, with ground visibility at one nm. There was no advantage, therefore, to descending even lower, since the approach lights, at that distance, would not be any more visible.

2.2.2.6 Possible Scenarios

As the aircraft approached MDA, the PNF would normally have called out “100 to go” and, while monitoring the approach, performed a visual scan outside to acquire visual references. During this time, the PF would be focused exclusively on his instruments to begin levelling off the aircraft at the MDA and maintaining this altitude. The PF would then wait for the PNF‘s callout (“Altitude Contact”; “No Contact”; “Approach Lights”; or “Runway in Sight”) before shifting some of his attention outside to acquire the visual references.

The investigation determine that there was probably no levelling–off at MDA and no significant distraction at this stage of the approach. It follows that the PF‘s attention must have shifted outside at the time when the level–off to MDA should have been performed. In this context, 2 plausible scenarios remain:

  • Both pilots were looking outside in the hope of acquiring visual references because they believed that the runway was close in front; or
  • The pilots saw lights in the distance, which induced them to focus their attention outside in order to continue the approach.

Pilots who regularly use the approach to Runway 12 at CYRC know that, once they pass the service station lights, the runway is imminent. However, the intensity of the lighting at the mine had increased considerably since the PF had received professional training at CYRC. It was therefore possible to confuse the mine for the service station. The composite image created following the test flights shows that the distance between the mine lights on approach and the accident site is approximately the same as the distance between the service station and the threshold of Runway 12 (Figure 2).

The aircraft reached MDA just after passing the mine lights. It is conceivable that, as they were passing, the pilots confused the mine lights for the service station lights located one nm from the runway threshold. Consequently, it is plausible that, as they were levelling off at MDA, the 2 pilots focused their attention outside the aircraft in an effort to see the approach lights.

The investigation confirmed that the ARCAL system had not been activated before the accident. Therefore, the approach, runway and airport lights were not illuminated when the aircraft descended below MDA. However, it is possible that the service station lights were visible from a distance when the aircraft reached MDA, since flight visibility can vary considerably from region to region in snow shower conditions. This is particularly true at night when flight visibility can be up to twice the visibility on the ground if lights are being observed.

The test flights revealed that the accident site was located in an area of the approach devoid of lights. The crew was, therefore, flying over unlit terrain with the service station lights possibly visible in the distance. The PNF would normally have called the lights in sight and it is probable that the PF shifted his focus outside to see them. Consequently, it is possible that both pilots were victims of a black hole illusion. In such conditions, it would be difficult to correctly estimate height because the pilots would feel that they were higher than was actually the case and would have believed they were on an acceptable approach path until the initial contact with the treetops.

Given the number of hours spent performing tasks related to driving a car and flying an aircraft in conditions requiring heightened visual focus, it is possible the crew was experiencing task induced fatigue. Given that such fatigue has a negative effect on visual and cognitive performances, it is possible that the ability to concentrate, operational memory, perception and visual acuity were all diminished. The effects of the task–induced fatigue possibly increased the difficulty in acquiring and subsequently interpreting the visual references required to safely continue the descent below MDA.

2.3 Risk Assessment and Mitigation of Non–precision Approaches

Air taxi operators generally serve regional airports that, in most cases, are only equipped with non–precision approach capabilities. The 1217 non–precision approaches in Canada account for 91% of all the CAP–published approaches. The FSF ALAR task force determined that the risk of ALAs was 5 times higher for non–precision approaches than precision approaches. In addition, the majority of accidents involving air taxi operations are ALAs, which account for 70% of all commercial operation ALAs.

As CFIT accidents cause significant damage and generally result in loss of life, based on the ICAO definition, the severity of such an occurrence is considered catastrophic.

TSB data indicate that there were 230 ALA accidents involving air taxi operations over the past decade–on average 12 times more than were sustained by airline operations. It is reasonable to conclude that other ALA accidents are likely to occur; therefore, the probability of an ALA occurring is either occasional 71 or remote. 72

The risk is defined based on a prediction of probability and the severity of consequences. It is not possible to reduce the catastrophic consequences of a collision with the ground, and the probability of an ALA occurring is real. In these conditions, ICAO‘s risk tolerability matrix indicates that strategies to control or mitigate the risks must be put in place so that the risks can be reduced to as low as reasonably practicable for non-precision approaches.

This ALA risk is known and documented and there are formal evaluation and prevention tools to address it.

2.4 ALA Risk Mitigation Actions

2.4.1 General

In an effort to reduce ALA accidents, several ICAO member states, including all the countries in the European Union, have chosen to implement the actions recommended by the FSF ALAR task force, along with the recommendations in Annex 4 for improving the visual aspect of charts used in connection with non–precision instrument approaches.

2.4.2 Instrument Approach Design

According to the CARs, the design of the RNAV (GNSS) Runway 12 approach at CYRC is compliant with the TP308 standards. However, by focusing primarily on obstacle clearance for the design of instrument procedures, international efforts to reduce ALAs, including the final approach based on an optimum descent path of 3°, are not taken into consideration.

As a result, the RNAV (GNSS) Runway 12 approach at CYRC, which does not include any significant obstacles on approach, was designed with a FAF crossing altitude of 763 feet above the runway threshold at a distance of 5 nm. As this is the only altitude for crossing the FAF published in CAP, pilots generally use it as a target. In these circumstances, the descent angle is only 1.35°.

In 1998, TC published an article on CFIT that asked the question: Why are aircraft flying at minimum IFR altitudes on non-precision approaches? The article examines the role of pilots and not systemic aspects that may affect their performance. According to Dekker’s perspective on human error 73 , blaming an individual rather than trying to understand a situation from the individual’s standpoint avoids identifying and solving the real problems.

The same article was reprinted 13 years later, with an acknowledgement that the problem continues to exist in 2011. According to Hollnagel 74, it is recognized from an accident prevention standpoint that a reminder to be careful when facing certain risks is not an efficient safety strategy. The risk needs to be counteracted by restructuring or by introducing safety measures aimed at protecting the individual against such a risk.

According to data compiled by the TSB, the ALA rate for commercial operations seems to have generally decreased very little over the past 10 years. It would appear, therefore, that the strategy employed by TC has not been effective.

2.4.3 Instrument Approach Depiction

The RNAV (GNSS) approach chart for Runway 12 at CYRC published in the CAP does not meet all the depiction standards outlined in Annex 4, since the descent angle does not appear on the charts. Consequently, pilots flying non-precision approaches in Canada do not benefit from a visual reminder, indicating for this particular approach, that if it is flown at the published altitudes, the descent angle is only 1.35° instead of the recommended optimum 3°.

The RNAV (GNSS) approach chart for Runway 12 at CYRC published in the CAP does not incorporate all of the depiction recommended practices in Annex 4, and TC does not require compliance with them. Consequently, the approach charts published in the CAP exclude the visual aspects recognized for their beneficial effects on positional awareness relative to terrain, such as:

  • Angle of descent
  • Depiction of the optimum descent path
  • Altitude/distance table
  • Profile of terrain below the approach

Figure 8. RNAV (GNSS) profile - Runway 12
Figure 8. RNAV (GNSS) profile – Runway 12 ↑

The only line with an arrow appearing on the RNAV (GNSS) approach chart profile for Runway 12 shows what appears to be the course to be flown (Figure 8). According to the designers, these altitudes are obstacle clearance minimums and pilots should not necessarily follow them. In 1998 and again in 2011, articles published by TC asked why pilots fly at these altitudes. However, no other options are indicated on the chart and TC does not publish formal reference documents to explain instrument flight procedures in Canada.

The descent profile is not shown to scale. Consequently, the horizontal distance to descend 400 feet between ESRIX and OTUTI is almost the same as to descend 40 feet after OTUTI to the MDA. Visually, this similarity in horizontal distance could create a false perception of the time required to descend to the MDA after OTUTI, and could mask the fact that the angle of descent is 1.35° instead of the recommended 3° optimum path.

Using an altitude/distance table is cognitively easier when executing and monitoring a descent on final, since the calculations are already made and it is simply a matter of comparing the altitudes and distances. Given the possibility that the crew was experiencing task–induced fatigue, which has a negative effect on the operational memory used for mental calculations, the use of such a table would reduce the risk of error when performing the descent.

Approach charts published in the CAP do not include terrain profiles. A pilot must, therefore, develop knowledge of the height above the terrain by means of deduction, which, in and of itself, requires greater cognitive effort than if the terrain were shown visually on the charts.

The instrument approach charts that incorporate the recommendations of Annex 4 provide a precise visual image of the path to be followed, while indicating the minimum obstacle clearance altitudes. These visual elements, which are recognized for their beneficial effects on positional awareness relative to terrain, reduce the required cognitive effort and, by extension, workload when flying an approach.

Figure 9. Descent profile incorporating Annex 4 recommendations
Figure 9. Descent profile incorporating Annex 4 recommendations ↑

Figure 9. Descent profile incorporating Annex 4 recommendations

2.4.4 Stabilized Constant Descent Angle Technique

The step–down descent relies on prospective memory, which requires a heavier workload and more cognitive effort than a SCDA descent. Consequently, one one hand, depending on whether a crew is tired or not, it is more vulnerable to making errors inherent to the execution of the step-down approach. The task simplification associated with the SCDA technique, on the other hand, enables the cognitive effort required for the approach to be reduced, thereby reducing the workload and, by extension, the risk of error.

The benefits of the SCDA technique have been demonstrated and validated by TC and several international organizations. The use of the SCDA technique is mandatory for a number of commercial operators in various countries, including all operators in the European Union as of 16 July 2011. However, the vast majority of air taxi operators in Canada do not use the SCDA technique for non precision approaches.

Following the release of Commercial and Business Aviation Advisory Circular No. 238 in 2006, adoption of the SCDA descent technique has often been confused with the need to use it to benefit from the approach ban operations specification. TC approval is necessary to obtain operations specification. Consequently, a number of pilots believe, wrongly, that they cannot perform a SCDA descent without TC‘s prior approval.

The Instrument Procedures Manual (TP2076) did not cover the SCDA technique and, in 2010, TC decided to cease its publication. As a result, Canadian pilots must obtain technical information on SCDA approaches elsewhere. By using reference documents not based on Canadian approach design and depiction standards, pilots could possibly experiment with techniques that are not adapted to the information appearing on CAP published approach charts.

2.4.5 FSF Recommendations

The recommendations of the FSF ALAR task force have been recognized internationally as tools for mitigating the risks of approach and landing accidents. These recommendations cover all operational aspects, from the design and depiction of instrument approaches to company policies, SOPs, training and equipment on board aircraft.

Several of these recommendations touch upon relatively simple ways to reduce operational irregularities by clarifying company policies, such as including a precise definition of the stabilized approaches to be used and a go-around policy, without risk of reprimand. Other recommendations concern pilots, focusing on the role of the pilot in command in complex situations, the use of decision-making models, threat and error management, SOPs and training.

With respect to the occurrence flight, C–GPBA was equipped with a radio altimeter. However, the target altitude bug was set to 1500 feet agl , and therefore its light went on at 1500 feet agl. According to the task force’s recommendations, the radio altimeter should be set to 200 feet agl for this type of approach and the crew should be trained to perform an aggressive go–around if the radio altimeter light comes on without visual contact with the runway. In several of the plausible scenarios that were considered, this action alone might have avoided the impact with the trees.

The company, like many air taxi operators, was unaware of the FSF ALAR task force recommendations. The company had implemented what was required by the CARs, which only capture a few of the FSF ALAR task force recommendations.

2.4.6 FSF ALAR Task Force Tool Kit

IATA and ICAO both endorsed the FSF ALAR toolkit as a valuable aid for ALA prevention and recommended that this material be incorporated into training programs. ICAO then distributed 10 000 copies of the tool kit. Over 40 000 copies in total have been distributed around the world. Unfortunately, none of the operators or pilots interviewed as part of this investigation were familiar with the tool kit. Several of the measures cited in it are therefore not used in Canada, thus exposing crews and passengers to a higher ALA risk.

The crew of C–GPBA did not have at its disposal the ALA risk mitigation tools that are available around the world. The environment in which they conducted the approach was performed without the benefit of the defences within the ALAR toolkit. The pilots flew at the CAP published altitudes to perform the RNAV (GNSS) Runway 12 approach, doing so on the basis of their training and practices and because these were the only altitudes appearing on the chart. After crossing the FAF, the crew used the usual rate of descent corresponding to a 3° path. The aircraft found itself at the minima at 350 feet agl and 4 nm from the runway threshold, over an area without lights that is subject to a black hole illusion.

The company’s operations manual, SOPs, training, C–GPBA equipment and approach charts all complied with the CARs. The aircraft, not having levelled off at the minima, struck the trees 3 nm before the runway threshold. Therefore, this accident, in addition to other ALAs that have occurred in similar circumstances over the past few years, would seem to indicate that the measures in place for mitigating this accident risk are inadequate.

3.0 Conclusions

3.1 Findings as to Causes and Contributing Factors

  1. For undetermined reasons, the crew continued its descent prematurely below the published approach minima, leading to a controlled flight into terrain (CFIT).

3.2 Findings as to Risk

  1. The use of the step-down descent technique rather than the stabilized constant descent angle (SCDA) technique for non-precision instrument approaches increases the risk of an approach and landing accident (ALA).
  2. The depiction of the RNAV (GNSS) Runway 12 approach published in the Canada Air Pilot (CAP) does not incorporate recognized visual elements for reducing ALAs, as recommended in Annex 4 to the Convention, thereby reducing awareness of the terrain.
  3. The installation of a terrain awareness warning system (TAWS) is not yet a requirement under the Canadian Aviation Regulations (CARs) for air taxi operators. Until the changes to regulations are put into effect, an important defense against ALAs is not available.
  4. Most air taxi operators are unaware of and have not implemented the FSF ALAR task force recommendations, which increases the risk of a CFIT accident.
  5. Approach design based primarily on obstacle clearance instead of the 3° optimum angle increases the risk of ALAs.
  6. The lack of information on the SCDA technique in Transport Canada reference manuals means that crews are unfamiliar with this technique, thereby increasing the risk of ALAs.
  7. Use of the step–down descent technique prolongs the time spent at minimum altitude, thereby increasing the risk of ALAs.
  8. Pilots are not sufficiently educated on instrument approach procedure design criteria. Consequently, they tend to use the CAP published altitudes as targets, and place the aircraft at low altitude prematurely, thereby increasing the risk of an ALA.
  9. Where pilots do not have up-to-date information on runway conditions needed to check runway contamination and landing distance performance, there is an increased risk of landing accidents.
  10. Non–compliance with instrument flight rules (IFR) reporting procedures at uncontrolled airports increases the risk of collision with other aircraft or vehicles.
  11. If altimeter corrections for low temperature and remote altimeter settings are not accurately applied, obstacle clearance will be reduced, thereby increasing the CFIT risk.
  12. When cockpit recordings are not available to an investigation, this may preclude the identification and communication of safety deficiencies to advance transportation safety.
  13. Task–induced fatigue has a negative effect on visual and cognitive performance which can diminish the ability to concentrate, operational memory, perception and visual acuity.
  14. Where an emergency locator transmitter (ELT) is not registered with the Canadian Beacon Registry, the time needed to contact the owner or operator is increased which could affect occupant rescue and survival.
  15. If the tracking of a call to 911 emergency services from a cell phone is not accurate, search and rescue efforts may be misdirected or delayed which could affect occupant rescue and survival.

3.3 Other Findings

  1. Weather conditions at the alternate airport did not meet CARs requirements, thereby reducing the probability of a successful approach and landing at the alternate airport if a diversion became necessary.
  2. Following the accident, none of the aircraft exits were usable.

4.0 Safety Action

4.1 Action Taken

4.1.1 Exact Air Inc.

To minimize the risks of Approach and Landing Accidents (ALA), the company implemented stabilized constant descent angle (SCDA) in its SOPs.

A program was set up to progressively install radio altimeters on the company aircraft.

The company controlled flight into terrain (CFIT) training was reviewed to integrate the recommendations of the flight safety foundation ALAR task force.

The following measures have been, or will be taken by Exact Air Inc. to reduce the operational risks:

  • The review of all departments related to flight operations.
  • A complete review of standard operating procedures (BE10, PA–31, PA–34, C–402).
  • A review of operational limitations of the charter operations (ie: new restrictions for new captains and first officers as well as equipment restrictions).
  • All flying personnel will redo the company CFIT course.
  • A risk analysis file is available to the flight crew to review level of the risk associated with approaches in IMC conditions for all destinations. This file is based on the Flight Safety Foundation program.
  • A flight safety awareness campaign called “Objectif Zéro” was setup to involve all Exact Air Inc. employees. The aim is to allow all employees to have a positive impact on flight safety via the company safety management system (SMS).

4.1.2 NAV CANADA

NAV CANADA supports the recommendations of International Civil Aviation Organization (ICAO) and those of the FSF ALAR task force. Templates for SCDA have been submitted as part of the overall format improvements to the instrument procedures in Canada.

In order to support global stabilized approach principles and ICAO recommended practices, NAV CANADA has developed the following CDA standards (constant descent angle):

CDA Principles:

  1. CDA standards will be applied to all fixed wing and helicopter non-precision instrument procedures
  2. The CDA table and profile view distances are aligned
  3. CDA distance tables will be provided for the intermediate (Intermediate fix or equivalent) and final segments
  4. Descent angles are limited to between and including 3.0 ° (nominal) to 3.5 ° for aircraft and 3.0 ° to 4.5 ° for helicopter
  5. A set of rules have been developed to indicate a minimum CDA intercept altitude for the final approach segment

The final helicopter CDA standard is still under development.

Production of the new format is ongoing and distribution will commence sometime in the near future.

4.2 Safety Action Required

4.2.1 Design and Depiction of Canadian Instrument Approach Procedures

TP308 states that the optimum descent path for a non–precision final approach segment is 318 feet per nm, or an angle of 3°, and its use is recommended. However, the design of the instrument approaches published in the Canada Air Pilot (CAP) is based primarily on obstacle clearance. This design does not incorporate the optimum 3° path to be flown, but rather a series of minimum obstacle clearance altitudes.

The depiction of the non–precision approach charts published in the CAP cannot display an optimum descent path because it is not factored into the design. The descent path depicted on the approach chart is a line connecting the minimum obstacle clearance altitudes, rather than the path to be flown.

Pilots misinterpret the line depicted in the CAP approach chart as the path to be flown. Depending on the obstacles present in the approach path, the resulting descent could be very shallow. Consequently, aircraft spend more time than necessary at altitudes that provide a minimum obstacle clearance, thereby increasing the risk of approach and landing accidents (ALA).

The instrument approach charts that incorporate the recommendations of Annex 4 provide a precise visual image of the path to be followed, while indicating the minimum obstacle clearance altitudes. These visual elements are recognized for their beneficial effects on positional awareness relative to terrain, reduce the required cognitive effort and, by extension, workload when flying an approach.

Therefore, the Board recommends:

The Department of Transport require that the design and depiction of the non-precision approach charts incorporate the optimum path to be flown.

A12-01

4.2.2 Stabilized Constant Descent Angle (SCDA)

There are essentially 2 techniques for completing the final descent on a non-precision approach: step–down descent and final descent on a stabilized constant descent angle (SCDA).

The step–down descent technique involves flying an aircraft to a series of published minimum altitudes. This requires multiple changes in attitude and power to maintain a constant speed throughout the descent. The technique relies on prospective memory, which requires a heavier workload and more cognitive effort than a SCDA descent. Consequently, whether a crew is tired or not, they are more vulnerable to making errors inherent in the execution of the step-down approach.

The SCDA technique involves intercepting and maintaining an optimum descent angle to MDA. The descent is therefore flown at a constant angle and constant rate of descent, requiring no configuration change. The task simplification associated with the SCDA technique reduces the cognitive effort required for the approach, thereby reducing the workload and, by extension, the risk of error.

The benefits of the SCDA technique have been demonstrated and validated by TC and several international organizations. However, the majority of operators in Canada do not use the SCDA technique for non precision approaches.

The FSF ALAR task force determined that the risk of ALAs was 5 times higher for non–precision approaches than for precision approaches. Non–precision approaches make up 91% of all approaches published in the CAP.

The use of the SCDA technique as an additional defense mechanism would help mitigate the risk of an ALA associated with non-precision approaches.

Therefore, the Board recommends:

The Department of Transport require the use of the stabilized constant descent angle approach technique in the conduct of non-precision approaches by Canadian operators.

A12-02

4.3 Board Concern

4.3.1 FSF ALAR Task Force Recommendations

In 1998, the Flight Safety Foundation (FSF) Approach and Landing Accident Reduction (ALAR) task force issued recommendations targeting the reduction and prevention of the ALA. An ALAR Toolkit which incorporates these recommendations was developed and distributed by the FSF as a resource. These FSF recommendations have been recognized internationally as tools for mitigating the risks of ALA.

In 1998 and 1999 Transport Canada (TC) published articles related to the reduction of CFIT accidents. Both articles make reference to the FSF ALAR Toolkit. The 1998 TC article was reprinted 13 years later.

To date, approximately 40 000 copies of the toolkit have been distributed worldwide. However, the majority of Canadian air taxi operators has not reviewed the contents of the ALAR Toolkit and is unaware of the details of FSF recommendations. Therefore, these recognized mitigation strategies for reducing ALAs are not being implemented into their operations.

Between 2000 and 2009, TSB data indicate that the Approach and Landing Accidents (ALA) rate for commercial operations seems to have decreased only slightly and the number of fatalities has remained constant. During this period, there were 230 ALAs involving air taxi operations — on average 12 times more than were sustained by airline operations.

Therefore, past efforts to promote the use of the FSF recommendations have not succeeded in their implementation into commercial operations and the number of fatalities resulting from ALAs has remained constant.

The Board is concerned that, despite past efforts, recognized mitigation strategies to reduce ALAs found in the FSF recommendations, are not being implemented into commercial operations.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 08 March 2012


Appendix A — RNAV (GNSS) Runway 12 – CAP

Appendix A - RNAV (GNSS) Runway 12 - CAP
Appendix A – RNAV (GNSS) Runway 12 – CAP

Appendix B — Graphical Forecast Area

Appendix B - Graphical Forecast Area
Appendix B – Graphical Forecast Area

Appendix C — Examples of Descent Profiles

Example of EU chart
Appendix C – Example of EU chart (Jeppesen)

Example of approach in Japan
Appendix C – Example of approach in Japan (Jeppesen)

Airservices Australia ©, YPAD RNAV-Z (GNSS) RWY 5
Appendix C – YPAD RNAV-Z (GNSS) RWY 5 (Airservices Australia)

Appendix D — Safety Risks (ICAO Doc 9859 AN/474)


Appendix D – Safety Risks (ICAO Doc 9859 AN/474)


Appendix D – Safety Risks (ICAO Doc 9859 AN/474)


Appendix D – Safety Risks (ICAO Doc 9859 AN/474)


  1. All times Eastern Standard Time (Coordinated Universal Time minus 5 hours). ↑
  2. PF (pilot flying) – Member of the flight crew who is at the controls, as defined in the standard operating procedures. ↑
  3. PNF (pilot not flying) – Member of the flight crew who is not at the controls, but who is monitoring the flight or approach parameters as defined in the standard operating procedures. ↑
  4. All altitudes are above sea level (asl) unless otherwise stated. ↑
  5. The International search and rescue satellite system. ↑
  6. Air Traffic Control Manual of Operations (MANOPS) 6.24.1 A.1.  ↑
  7. CRTC Telecom Regulatory Policy CRTC 2009-40. ↑
  8. CRTC, 01 February 2010, Wireless enhanced 911 (E911) services. http://www.crtc.gc.ca/eng/info_sht/t1035.htm. Website address confirmed accessible as of report release date. ↑
  9. Subpart 602.123 of the CARs, Alternate Aerodrome Weather Minima ↑
  10. Official Journal of the European Union, Commission Regulation (CE) No 859/2008 (EU-OPS1). ↑
  11. Jongman, L., Meijman, T., & de Jong, R., The working memory hypothesis of mental fatigue, 1999.
    Boksem, M.A.S., Meijman, T.F., Lorist, M.M, “Effects of mental fatigue on attention: An ERP study”, Cognitive Brain Research, 25 (2005).
    Ackerman, P.L. (ed.), Cognitive Fatigue: Multidisciplinary Perspectives on Current Research and Future Applications, 2010.
    Leonard J. Trejo, L.J., Kochavi, R., Kubitz, K., Montgomery, L.D., Rosipal, R., Matthews, B., “Measures and Models for Estimating and Predicting Cognitive Fatigue”, Proceedings of the 44th Annual Meeting of the Society for Psychophysiological Research, Santa Fe, U.S. (2004). ↑
  12. Standard 723.16 of the CASS, Operational Control System ↑
  13. Operations Specification 100 (Part IV)  ↑
  14. Standard 723.98(29) of the CARs, Controlled Flight into Terrain (CFIT) Avoidance Training ↑
  15. International Civil Aviation Organization, Human Factors Training Manual, First Edition, 1998 ↑
  16. CARs, Part V, Subpart 71, ↑
  17. Q-1030 maintenance schedule for the BE10 ↑
  18. Government of Canada, OnlineCanadian Beacon Registry of the Government of Canada, http://www.canadianbeaconregistry.forces.gc.ca. Website address confirmed accessible as of report release date. ↑
  19. Subsection 605.33(2) of the CARs, Flight Data Recorder and Cockpit Voice Recorder ↑
  20. Beech A100 certificate (BE-10A14CE) ↑
  21. Subpart 703.86 of the CARs, Minimum Crew ↑
  22. Operations Specification 011 (Part IV), Minimum Crew ↑
  23. Standard 723.86, Single Pilot IFR Requirements ↑
  24. Subpart 703.66 of the CARs, Additional Equipment for Single-pilot Operations ↑
  25. Supplemental Type Certificate (STC) SA00705WI and STC SA00864WI ↑
  26. FAA FAR 135.154, Terrain awareness and warning system ↑
  27. FAA-H-8261-1A, Instrument Procedures Handbook, Pages 1-5, 1-6 ↑
  28. Council Regulation (EEC) No 3922/91, Common technical requirements and administrative procedures applicable to commercial transportation by aeroplane/OPS 1.665 – Ground proximity warning system and terrain awareness warning system ↑
  29. ATSB R20060008 ↑
  30. TSB Investigation Report No. A90H0002 ↑
  31. Highest altitude of the first 3000 feet of runway ↑
  32. Section 703.40 of the CARs , Instrument Approach Procedures ↑
  33. TP14371 – Aeronautical Information Manual, 1.6.4 ↑
  34. AFTN: aeronautical fixed telecommunication network  ↑
  35. Section 602.104 of the CARs , Reporting Procedures for IFR Aircraft When Approaching or Landing at an Uncontrolled Aerodrome ↑
  36. TSB Investigation Report A07Q0213 ↑
  37. Transport Canada, TP14371, 4.5.7 ↑
  38. TSB report A08Q0231 ↑
  39. Canadian Air Navigation Services Commercialization Act (CANSCA). ↑
  40. Subsection 803.01(2) of the CARs, Provision of Aeronautical Information Services. ↑
  41. Annex 4 to the Convention, 11.10.8.5. ↑
  42. Annex 4 to the Convention, 11.10.8.4.  ↑
  43. Annex 4 to the Convention, 11.10.6.5. ↑
  44. Rasmussen, SRK taxonomy = “Knowledge-based task.” ↑
  45. Also referred to as “reduced intentionality.” Occurs when there is a delay between the intention to perform a planned task and its execution. When the appropriate checks are not made, the planned task gives way to other demands. ↑
  46. Problems relating to prospective memory were also addressed in TSB investigation report No. A09W0037. ↑
  47. Rasmussen, SRK taxonomy = “Skill-based task” wherein actions are based on learned routines and there are few, if any, conscious decisions to be made. ↑
  48. Rasmussen, J. Skills, “Rules, knowledge; signals, signs, and symbols, and other distinctions in human performance models”, IEEE Transactions on Systems, Man and Cybernetics, 13 (1983). ↑
  49. Aircraft Accident Report NTSB/AAR-96/05, Collision with Trees on Final Approach.  ↑
  50. Aircraft Accident Report NTSB/AAR-06/01, Collision with Trees and Crash Short of the Runway. ↑
  51. Instrument Procedures Handbook (FAA-H-8261-1A) ↑
  52. Airplane Flying Handbook (FAA-H-8083-3A) ↑
  53. FAA Advisory Circular No. 120-108, dated 20 January 2011 ↑
  54. Official Journal of the European Union, Annex III, Common technical requirements and administrative procedures applicable to commercial transportation by aeroplane, Subpart E, ALL WEATHER OPERATIONS, OPS 1.430 Aerodrome operating minima – General ↑
  55. OPS 1.430 d) 1) ↑
  56. OPS 1.430 d) 2) ↑
  57. Jeppesen Briefing Bulletin (JEP 08-D), Aerodrome Operating Minimums According to EU‑OPS 1, 26 September 2008. ↑
  58. These accidents include all types of operation (private and commercial) and all types of aircraft (planes, advanced ultralights and helicopters). ↑
  59. Flight Safety Foundation Approach-and-landing Accident Reduction (ALAR) Task Force. ↑
  60. A point that an aircraft must overfly at a defined height before manoeuvring for final approach. ↑
  61. A Human Error Analysis of General Aviation Controlled Flight Into Terrain Accidents Occurring Between 1990-1998. ↑
  62. National Aerospace Laboratory NLR, Amsterdam, The Netherlands – NLR TP97270. ↑
  63. ATSB, Aviation Research and Analysis Report – B2006/0352. ↑
  64. TC, Airspace Newsletter – 1/98. ↑
  65. TC, Air Carrier Advisory Circular, No. 0161. ↑
  66. Transport Canada, Commercial and Business Aviation Advisory Circular, No. 0238, 08 September 2006. ↑
  67. Aircraft registered in Canada only. ↑
  68. TSB investigation reports A08W0244, A08O0036, A08O0333, A09C0012 and A09Q0203. ↑
  69. ICAO, Safety Management Manual (SMM), Doc 9859, AN/474, paragraph 5.2.8. ↑
  70. In stressful or heavy workload situations, people may revert to learned or habitual behaviours. In situations where their behaviour is not applicable to the context, a negative transfer takes place. ↑
  71. Likely to occur sometimes (has occurred infrequently). ↑
  72. Unlikely to occur, but possible (has occurred rarely). ↑
  73. Dekker, S.W.A. (2002). The field guide to human error investigations. Ashgate Publishing Ltd: Aldershot, United Kingdom ↑
  74. Hollnagel, Erik (2004). Barriers and Accident Prevention. Ashgate Publishing Ltd: Aldershot, United Kingdom ↑

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Aviation Reports – 2010 – A10P0244

| Transportation Safety Board Reports | April 27, 2012

Transportation Safety Board of Canada

Aviation Reports – 2010 – A10P0244

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Collision with Terrain
Conair Group Inc.
Convair 580 C–FKFY
Lytton, British Columbia, 9 nm SE
31 July 2010

Report Number A10P0244

Synopsis

On 31 July 2010 at 2002 Pacific Daylight Time, Conair Group Inc.’s Convair 580 (registration C–FKFY, serial number 129) operating as Tanker 448 departed Kamloops to fight a wildfire near Lytton, British Columbia. The bombing run required crossing the edge of a ravine in the side of the Fraser River canyon before descending on the fire located in the ravine. About 22 minutes after departure, Tanker 448 approached the ravine and struck trees. An unanticipated retardant drop occurred coincident with the tree strikes. Seconds later, Tanker 448 entered a left–hand spin and collided with terrain. A post–impact explosion and fire consumed much of the wreckage. A signal was not received from the on–board emergency locator transmitter; nor was it recovered. Both crew members were fatally injured.

Factual information

History of flight

The aerial firefighting operation involved 2 aircraft: a bird dog aircraft (Rockwell Turbo Commander 690) and a tanker aircraft (Convair 580, called Tanker 448). The bird dog crew planned and directed the fire suppression activity, which included a demonstration of the bombing run and a verbal description for the tanker crew as they circled above. The tanker crew would then complete the same run and make the retardant drop as described.

The plan was for Tanker 448 (T448) to make 8 left–hand circuits, dropping 18 of its retardant load each time. The terrain imposed a requirement to modify the standard rectangular circuit 1 to a triangular–shaped circuit (Figure 1). This consisted of flying a combined downwind/base leg from the Fraser River northbound over the rising east side of the canyon to a point at the edge of the ravine.

A single left turn to final required a change of direction greater than 90° at a bank angle of up to 40°. T448 then had to descend 900 feet into the ravine to make the drop. After each drop, T448 was to proceed straight ahead over descending terrain in the ravine back toward the Fraser River.

Figure 1 - Estimated flight path
Figure 1. Estimated flight path ↑

Normally, the Conair tanker procedure is to leave the circuit altitude at 1000 feet above the desired drop height on the base leg and level out at the desired drop height during the final approach leg. The modified circuit required T448 to maintain an altitude of 3100 feet above sea level (asl) until it crossed the edge of the ravine. This altitude provided about 100 to 150 feet of clearance above the trees where the bird dog aircraft had crossed the edge of the ravine. T448 could then turn final while descending 900 feet to the drop height.

The planned route and briefing included a safety exit which consisted of a left turn from any point along the downwind/base leg to proceed over descending terrain back toward the Fraser River.

An electronic tracking device installed on T448 transmitted a global positioning system (GPS) position report every 2 minutes. The data transmitted indicated that T448 had completed 2 orbits above the fire area while the bird dog aircraft demonstrated the bombing run. T448 joined the circuit for its first bombing run close to the Fraser River and then proceeded south–southwest at an altitude of 3432 feet asl and a groundspeed of 140 knots. This was consistent with Conair standard operating procedures (SOP). The last 36 seconds of the flight were captured on video taken from the bird dog aircraft.

Before the tree strikes, the aircraft appeared to be flying in a nose–high attitude with wing flaps selected to an undetermined extension and the landing lights (on the bottom of the wings) extended and illuminated. No safety exit turn was initiated and there were no radio communications during the circuit. All prior communications were normal. About 3 seconds before the tree strikes, the bird dog crew observed a change in T448‘s flight profile, which was interpreted as a change from level flight to descent.

An unanticipated retardant drop occurred coincident with the tree strikes. About 3 seconds later, T448 entered the left–hand spin 2 which continued for 1 revolution in 5 seconds in a steep nose–down attitude before the aircraft struck terrain 590 feet below.

Accident Site

There were 2 sites associated with this accident: the site of the tree strikes at the edge of the ravine, and the main accident site at the bottom of the ravine. T448 struck 3 trees on a knoll at the edge of the ravine at approximately 3020 feet asl about 8 seconds before the crash.

It could not be determined if T448 approached the exact location where the bird dog had crossed the edge of the ravine. Since the edge of the ravine generally sloped down from right to left, a track further to the right would encounter higher terrain.

The pattern of broken tree tops suggests the aircraft was climbing. Retardant was not found on the trees that were struck but rather 30 feet beyond.

The only aircraft debris found at the site of the initial tree strikes was a small washer, which was identified as a nut locking clip used to secure composite panels that cover the elevator hinges.

Video footage did not reveal any pieces leaving the aircraft in flight and none were found between the tree strikes and the main accident site.

Tree damage at the main accident site indicated that the final descent angle was 51°. The aircraft was carrying nearly a full load of retardant and a significant volume of fuel. The ground impact produced a fireball and the post–impact fire started another wildfire.

Post–impact fire damage was extensive and therefore limited the wreckage examination.

Weather

The 2000 3 aviation routine hourly weather report (METAR) issued by an automatic observation station at Lytton, 9 nautical miles (nm) up–river from the accident site, reported the following: wind 170° true at 24 knots gusting to 30 knots, visibility 9 statute miles (sm) with a few clouds at 4500 feet above ground level (agl), temperature 22°C, altimeter setting 29.85 inches of mercury (Hg).

The video coverage showed smoke rising and drifting slowly from the target fire. The bird dog hand–held camera remained stable during the filming. Both of these factors demonstrate light wind and that the bird dog aircraft did not encounter turbulence or downdraughts. Weather was not a factor in this accident.

Flight crew

Records indicate that the flight crew was certified and qualified for the flight in accordance with existing regulations. The captain held an airline transport pilot licence (ATPL) and had been employed by the operator since 1983. The captain had completed recurrent training in April 2010; the training included a pilot proficiency check/instrument flight test, as well as controlled flight into terrain (CFIT) avoidance (including prevention strategies and escape manoeuvre techniques and profiles) and pilot decision making/cockpit resource management. The first officer was assigned to this captain for line indoctrination training.

The first officer (FO) held an ATPL and was hired in May 2010. The FO had completed initial training, including a pilot proficiency check and instrument flight test in June 2010. As had the captain, the FO had training in CFIT avoidance, pilot decision–making/cockpit resource management, as well as aerial work and firefighting procedures. The FO was new to fire suppression operations and also new to the Convair 580 (CV580) (Table 1).

Table 1. Crew experience
Crew experience Total flight time Fire suppression experience CV580 experience
Captain 17 000 hours 3500 hours 900 hours
First officer 5200 hours 26 hours 34 hours

The Conair training syllabus for a new FO allocated 1 hour of flight time to firefighting procedures training, which included terrain flying, approach to target area, overshoot, airspeeds, altitudes, and crew coordination. Operation of the aircraft at its maximum gross take–off weight (MGTOW) and an actual emergency drop (E–drop) of the retardant load were not included in the syllabus.

The crew’s duty day began at about 1000 and included a 3–hour break from 1640 to 1940. Tanker action on the fire near Lytton was initiated at 1951. A review of duty schedules and the 72–hour history for both pilots did not identify fatigue as a factor.

Engine and Propeller Examination

Both engines and their associated components were extensively damaged by impact and fire. No engine accessories could be tested. To the extent that it was possible, examination of the engines suggests that they were producing maximum power at the time of impact.

The damage to both propellers was consistent with the blades striking terrain while under significant power. Examinations determined that both propellers were functioning normally.

Flight Control Examination

Flight control surfaces were extensively damaged by impact and fire. From the limited examinations that could be performed, no issues of concern were identified. Wing flaps were broken into many sections but sustained the least fire damage. The left wing hydraulic flap–drive motor was recovered, and examination determined that the flaps were extended to 12° at the time of impact. Wing flaps operate through the normal aircraft hydraulic system and are activated by a momentary–on switch. Flaps travel between 2° and 3° per second as long as the switch is held. The hydraulic system is normally depressurized by a crew selection for cruise flight. Selecting the hydraulic system to the pressure position is an item contained in the BOMBING CHECK checklist.

The differential torque tube, located in the fuselage belly between the inboard flaps, was examined. This assembly arrests further flap operation in the event of a split flap condition. There were indications of differential movement between the right and left wing flaps, but it could not be determined if this was a result of the initial tree strikes or the final impact or a flap dissymmetry. Review of the video did not show any rolling motion by the aircraft during the 3 seconds before the left turn that precipitated the spin, as would be expected if there were flap dissymmetry.

Bird Dog Procedures

The bird dog aircraft was a Rockwell Turbo Commander 690. This model operates at similar speeds to the CV–580.

The Conair company operations manual (COM) provides direction to bird dog aircraft pilots regarding limitations and considerations in the development of firefighting routes for air tankers, and includes the following:

Section 7.25 If the angle of bank must be increased beyond 30° to complete the turn, the area will still be considered suitable with the following restrictions:

  • The angle of bank at no time exceeds 45°.
  • The tanker pilot must be informed of a bank angle exceeding 30°.
  • If the angle of bank exceeds 45° during the turning radius then the area will be considered unacceptable.

For all bird dog aircraft and air tankers, it must be emphasized that the approach must carry considerations for pilot error, distractions, visibility impairments, aircraft malfunctions, traffic avoidance, etc. with adequate capabilities of a safe exit. Ensure that the exit routes for air tankers following a drop will lead into level or descending ground.

The bird dog aircraft was using the Kamloops altimeter setting of 29.74 in Hg and this setting was provided to and acknowledged by T448. This setting was 0.11 in Hg lower than the local altimeter setting reported for Lytton at 2000. The altimeters of both aircraft had been calibrated within the previous 24 months. The calibration tables indicated that they should have read within 2 feet of each other at the circuit altitude, which means that both flight crews would have had the same elevation reference to terrain for visual operations.

The bird dog crew had the benefit of flying consecutively lower circuits in the development of the bombing run to the target fire. The briefing from the bird dog to T448 included a description of the magnitude of the turn–to–final since it exceeded the normal parameters. Other than the bank angle of the turn–to–final, the bird dog aircraft did not encounter any issues of visibility impairment or other concerns while planning or conducting the demonstration run for T448 to observe.

Weight and Balance

The accident aircraft was modified in accordance with several Canadian supplemental type certificates which allowed for progressively higher MGTOW. The accident aircraft was approved for a MGTOW of 58 500 pounds. The aircraft departed Kamloops with a full load of retardant and nearly 8000 pounds of fuel. A weight and balance calculation showed that, at take–off, the aircraft was about 480 pounds over its MGTOW which placed it outside of the certificated limitations. By the time T448 was on the approach to the fire, enough fuel would have been consumed to place the aircraft weight and centre of gravity within the approved limitations.

Tanker Procedures

Conair’s SOP recommend a maximum flap setting of 20° and an indicated airspeed of 140 knots for manoeuvres in a fire zone (5 nm radius). When in the circuit on the bombing run, wing flaps are normally extended to 30° with a target speed of 130 knots on the base leg, and to 40° with a target speed of 120 knots on the final leg. The anticipated go–around procedure following a drop for the CV–580 requires maximum–except–take–off (METO) power and flaps at 20°.

To comply with the initial firefighting plan, the flight crew had to set the retardant release selector to 18 of the tank capacity at maximum coverage and arm the system in accordance with the Conair CV580 BOMBING CHECK checklist. This set–up energized the normal drop switch on the left–hand grip of the left control wheel, which needs to be pushed to drop a load. The normal drop and communications (Com) switches were both operated by the pilot’s left thumb and were located in proximity to each other. The normal drop switch was unreachable from the right seat and was protected from unintentional operation by a collar around the switch. The doors on the retardant tank operate through the aircraft normal hydraulic system and incorporate an emergency hydraulic accumulator to permit operation if the normal system were to fail.

photo 1. E-Drop Switch
Photo 1. E–Drop Switch

The retardant delivery system included a separate emergency drop function to jettison the entire load in an emergency situation. The emergency drop switch was within reach of both pilots (Photo 1). It was determined that only part of the retardant load was jettisoned on the accident flight, which was consistent with the plan to drop18 of the load each time. It could not be determined if an emergency drop (E–drop) was verbally commanded or physically attempted, but it was unsuccessful.

Conair had previously identified 2 hazards associated with retardant loads: unintended load retention and unintended load jettison. The following policies were developed to mitigate these risks.

Regarding unwarranted retention of the load, the Conair COM and CV580 aircraft operating manual (AOM) encourage tanker crews to drop the retardant load immediately if flight crew safety is in jeopardy:

  • Tanker pilots should be prepared to drop their load should an immediate improvement in performance be required. (Conair COM section 7.21.2 (a))
  • It should also be emphasized to air tanker pilots that if they inadvertently find themselves in a tight spot where manoeuvring becomes critical and the aircraft is being flown towards the edge of the performance envelope, in the interest of crew safety, the retardant load should be jettisoned immediately. (Conair COM section 7.25)
  • In the event that the safety of the aircraft and crew are in jeopardy, either pilot may jettison the remaining load and set power as required. (CV580 AOM section 3.19)

With respect to unwarranted jettison of the load, the Conair policy is described in the CV580 AOM section 2 (Emergency Procedures/General):

Any item that requires an irreversible action, or is a guarded switch (i.e. an E–handle, extinguisher discharge, fuel valve, etc.), will be confirmed prior to the action being taken. […] Of necessity, the “Jettison” action will require the Captain’s initiation, whether the Captain is the PF [4] or PNF [5]. This is because in most aircraft the Captain has the only drop button, the aircraft may not, in the captain’s opinion, be in a good position to jettison the load, and the Captain has the responsibility for the safety of persons and property on the ground. The Emergency Drop selector should only be used if the Captain’s drop button fails.

Aircraft Operation and Systems

Records indicate that the aircraft was certified, equipped and maintained in accordance with existing regulations and approved procedures. Unscheduled maintenance was performed immediately before the accident flight and consisted of replacing the #1 alternating current (AC) generator. The aircraft is equipped with 2 AC generators, one on each engine; both were checked for correct operation after the maintenance work was completed. No safety concerns were identified with this maintenance action or with the general condition of the aircraft. The aircraft did not have any other reported or deferred defects. The aircraft was neither equipped with cockpit voice (CVR) or flight data (FDR) recorders, nor was it required to be by regulation.

Conair maintenance personnel performed an inspection 6 of the retardant tank every 14 days. The inspection was performed 11 days before the accident; this inspection recommended a functional check of the E–drop system. However, a functional check may not be performed since opening the retardant tank doors results in spillage of residual retardant and creates environmental concerns on the airport apron. The normal flight checklists, or any other operational document available to the flight crew, do not contain any item requiring a functional check of the E–drop system by the flight crew in lieu of the maintenance inspection.

The retardant delivery system included a separate E–drop function activated through a switch located between the pilot seats on an aft–facing switch panel on the centre pedestal (Photo 1). This switch was 1 of 3 guarded switches on a panel of 6 adjacent switches which were located in proximity to the pilots’ elbows and which could be operated by either pilot. The system was functional any time both the aircraft electrical and hydraulic systems were energized. The system requires up to 5 seconds to jettison a full retardant load, approximately 18 000 pounds.

The CV–580 was certified without a stall warning device and T448 was not equipped with one. The stall speeds of the aircraft did not change due to the installation of the retardant aerial delivery system. The location of the retardant tank on the aircraft belly placed it in an area most vulnerable to impact damage; consequently, the extent of damage precluded meaningful examination. The aircraft was equipped with an angle–of–attack (AOA) indicator installed in accordance with a supplemental–type certificate (Photo 2).

Photo 2. Angle-of-attack (AOA) indicator
Photo 2. Angle–of–attack (AOA) indicator

The AOA indicator was located on the far left side of the captain’s instrument panel adjacent to the airspeed indicator. The AOA indicator was marked with color–coded arcs. It did not provide any aural or visual warning annunciations. The indicator needle and the coloured arcs (on the right–hand side of the instrument face) were not completely visible from the right pilot seat.

Conair training practices says that the AOA indicator should be a primary reference during low–level manoeuvring and that it is a responsibility of the PNF to announce deviations such as the AOA indicator needle trending upward through the 3 o’clock position toward the 12 o’clock position.

In Conair CV580 operations, there are 2 types of overshoot procedures used: the anticipated and the unanticipated overshoot. Both procedures are based upon a pre–determined minimum airspeed on the approach. The anticipated overshoot is used following a retardant drop. This procedure normally involves a power increase to maximum except take–off (METO) power and a flap retraction to the 20° position. The unanticipated overshoot is an unplanned event. This requires maximum available power, a flap setting of 15° and, if applicable, raising the landing gear.

This aircraft model is known to pitch up during an overshoot. In both procedures, the retraction of flaps will result in a reduction of lift as well as a reduction of drag. In accordance with Conair SOP, T448 could have been approaching the ravine at 140 knots with flaps set to 20° or 130 knots with flaps set to 30°. These figures can change at the captain’s discretion. Lower airspeeds can result in a state of low energy, commonly known as the back side of the power curve.

The Conair COM recognizes this risk in Section 7.24.2 which states:

Operation on the “back side of the power curve” also known as the “region of reversed command” is one in which a reduction in airspeed brings about a need for increased power if altitude is to be maintained.

The combination of low airspeed and high power settings (in level flight) will result in a high angle of attack. The normal solution to this situation is to increase power, increase airspeed or preferably a combination of both.

This flight regime may be entered by inadvertently getting too low while approaching a ridge, during an unusually “flat” approach to the target or in gusty wind conditions . . . At low altitude and without additional power available for acceleration, there may be no means of obtaining the performance necessary to clear obstacles . . . Since angles of attack are already high, a stall can occur on the overshoot, particularly if the exit requires immediate manoeuvring for terrain avoidance.

During a National Transportation Safety Board (NTSB) investigation, NTSBAAR–70–27, into a 1968 CV–580 accident, a qualitative flight test was conducted with a CV–580 to demonstrate the basic aircraft stability and control in the go–around configuration. It was found that the aircraft tended to pitch up with the application of maximum available power. The test indicated that airspeed can be maintained by exerting a (pushing) force on the control yoke of 47 pounds or less throughout the centre of gravity range. The aircraft also exhibited heavy pre–stall buffet and recovery characteristics were positive. All flight controls were effective in the deep buffet region of flight.

The NTSB report concluded that the accident CV–580 was in a climbing attitude with indicated airspeed (IAS) decreasing through 105 knots before initiating an overshoot with maximum power and flaps selected to 15°. The aircraft continued slowing in the climb with the gear retraction occurring at 85 knots. At 80 knots, an abrupt and rapid loss of altitude and sharp left turn occurred.

Visual Illusion

On the day of the accident, the bird dog aircraft crew did not report experiencing a visual illusion while demonstrating the flight path. When the bombing run flight path was flown by TSB investigators several weeks after the accident, a visual illusion was observed. During the combined downwind/base leg, at 3100 feet asl to 3200 feet asl proceeding toward the known site of the initial tree strikes, estimated 1 nm away, the site appeared to be about 400 feet to 500 feet below the aircraft altitude when it was actually 150 feet below. Unlike the accident flight where visibility was 6 to 9 sm in smoke, about 1 hour before sunset, the investigation flight was conducted under good daytime visual conditions.

Visual illusion has been identified as a contributing factor in other accident investigations. An illusion creates a false perception that may be described as a form of unrecognized spatial disorientation regarding terrain.

The TSB investigation, report number A03P0194, into the crash of a Lockheed L–188 Electra air tanker also in British Columbia, concluded that: “The characteristics of the terrain were deceptive, making it difficult for the pilots to perceive their proximity and rate of closure to the rising ground in sufficient time to avoid it.”

Additionally, an investigation, number 13807, conducted by the Canadian Forces Directorate of Flight Safety into the crash of a military DHC–6 Twin Otter in Alberta, concluded that visual illusion was a principal contributing factor.

The Aeromedical Training for Flight Personnel manual 7 includes the following:

Illusions give false impressions or misconceptions of actual conditions; therefore, aircrew members must understand the type of illusions that can occur and the resulting disorientation. Although the visual system is the most reliable of the senses, some illusions can result from misinterpreting what is seen; what is perceived is not always accurate. Even with the references outside the cockpit and the display of instruments inside, aircrew members must be on guard to interpret information correctly.

Spatial Disorientation TYPE I (UNRECOGNIZED) – A disoriented aviator does not perceive any indication of spatial disorientation. In other words, he does not think anything is wrong. What he sees—or thinks he sees—is corroborated by his other senses. Type I disorientation is the most dangerous type of disorientation. The pilot –unaware of a problem – fails to recognize or correct the disorientation, usually resulting in a fatal aircraft mishap:

  • The pilot may see the instruments functioning properly. There is no suspicion of an instrument malfunction.
  • There may be no indication of aircraft–control malfunction. The aircraft is performing normally.
  • An example of this type of spatial disorientation would be the height–depth–perception illusion when the pilot descends into the ground or some obstacle above the ground because of a lack of situational awareness.

The following TSB Laboratory reports were completed:

LP156/2010 – Instrument Analysis (Horsepower gauges)
LP163/2010 – Analysis of Turbine Splatter

These reports are available from the Transportation Safety Board of Canada upon request.

Analysis

General

For the aircraft to be climbing through 3020 feet when it struck trees, it had to have descended more than 400 feet along the circuit route after it joined the crosswind leg at 3434 feet asl. The investigation determined that both engines were delivering maximum power and both propellers were operating in the same, normal, manner at the time of the crash. There were no identifiable in–flight airframe failures or system malfunctions. The crew did not communicate any concerns or make any attempt to abort the bombing run. Therefore, the change of altitude during the circuit was not due to technical malfunction.

The operation of the landing lights and the flap setting confirms that the BOMBING CHECK checklist had been completed. The partial retardant drop confirmed that the hydraulic system was pressurized and operating normally and that the retardant delivery system was operational and was selected to the requested drop volume. Since the drop button could only be operated from the left seat, its operation confirmed that the captain was not incapacitated.

When the overshoot was initiated, the first priority was to clear the terrain. The required nose–down elevator control input could be accomplished by exerting a pushing force on the control wheel to prevent an aerodynamic stall. Since the aircraft was not yet near a position to make the planned retardant drop, it is unlikely that the pilot would have been flying with his thumb on the protected drop switch and operated it in error while attempting to push the nose down. The captain likely intended to drop the pre–selected load in an attempt to improve climb performance.

A left turn down the ravine was the only exit route to avoid terrain after striking the trees. However, it cannot be determined if the left turn was initiated by the crew either as a result of damage to the aircraft, or as a consequence of attempting a go–around in a low energy state. In any case, a loss of control occurred.

It is likely that the aircraft was damaged because trees were struck. It could not be determined exactly what effect this had on the controllability and the resulting spin.

Company Procedures

In accordance with proactive safety management practices, Conair had previously identified several safety issues such as:

  • low energy flight conditions;
  • visual illusions;
  • engine power management procedures;
  • impending stall awareness;
  • unwarranted retention or jettison of the retardant load; and,
  • emergency procedures for jettison of the retardant load.

Company policies, procedures, equipment and training had evolved to mitigate these risks. Despite these efforts, this accident occurred.

Conair training practices recommend that the AOA indicator be used as a primary reference during low–level manoeuvring for the PNF to announce deviations trending toward the yellow or red arcs.

However, the AOA indicator’s location made it difficult to see the entire needle and the colour–coded arcs on the instrument face from the right–hand pilot seat, which may limit effective use of this tool.

Operational Factors

Had the aircraft been equipped with recorders which survived the crash, information such as verbal exchanges between crew members regarding procedures, intentions, briefings, instructions, commands, systems operations, propeller speeds, etc. could have been identified from a CVR. Control inputs and system selections could have been identified from a FDR. In the absence of concrete data from recorders, the investigation looked at 2 possible operational factors:

  • The flight inadvertently entered a low energy condition approaching the ravine in an attempt to recover altitude.
  • A visual illusion affected the crew’s ability to recognize and assess the aircraft’s proximity to the rising terrain resulting in this being a CFIT accident.

It was established that T448 descended more than 400 feet early in the circuit and was flying in a slow climb toward the edge of the ravine. A slow climb, rising terrain and the lack of a good horizon reference, are criteria that could contribute to the development of a low energy condition. Regardless of engine power, the low energy condition may not have allowed the aircraft sufficient time to pull up and establish an adequate climb, even with the benefit of the partial retardant drop. Airspeed and AOA indicators should have provided visual indications of low energy conditions and impending stall awareness. But there was no audible or visual alert that would have drawn the crew’s attention to these indicators.

If the airspeed was low and an overshoot was commanded, the flaps would have to be retracted to 15°. This would result in a reduction in the initial rate of climb. The aircraft was interpreted as going into a descent when observed by the bird dog crew. However, the bird dog crew did not know that T448 was climbing. Without a horizon reference, a reduction of the climb angle could appear to the bird dog crew as a change from level flight to a descent. Maximum power and 12° of flap, as found, would be consistent with an attempted go–around. While retracting flaps for a go–around, inadvertently holding the flap selector switch for 1 additional second would result in 2° or 3° more flap retraction than the target setting of 15°. There is no performance data in the AOM to determine a potential rate of climb. However, this should not be an issue because the plan to climb out following the first intended drop and accelerate from 120 knots to 140 knots in the 20° flap configuration, with 78 of the load remaining on board, is indicative of the airplane capability at an appropriate airspeed.

Furthermore, a visual illusion may have affected the crew’s ability to recognize, or accurately assess the aircraft’s flight path relative to the elevation of the rising terrain which, unbeknownst to the crew, put the aircraft too low before the edge of the ravine.

The local terrain was mountainous and precluded a good horizon reference. The flight occurred during the last hour of daylight in growing shadows and some smoke, which are factors that affect visibility. The action to continue the bombing run rather than take the exit route and circle for another attempt or to jettison the retardant load to improve the climb performance suggests the crew did not recognize the imminent danger ahead of them and may have neglected the altimeter, believing it was reasonable to continue and assess their progress visually. The criteria (a slow climb, rising terrain, lack of a good horizon reference) conducive to a low energy condition can also be conducive to a visual illusion producing a false sense of height, as observed during the TSB investigation flight.

Given the last–second response to avoid a collision with terrain at the edge of the ravine, and the partial retardant load drop, it is likely the crew was under the influence of a visual illusion. The aircraft’s proximity to terrain came as a surprise to the crew and as a result, affected the crew’s decisions and actions leading up to the event.

The bird dog pilot, however, had the benefit of flying consecutively lower circuits in the development of the bombing run to the target fire, and lighting conditions may have been slightly different. This opportunity may have reduced the likelihood of a height or depth–perception illusion, and illusions were not discussed in any briefings to T448.

Emergency Drop System

The crew likely recognized very late that a collision with trees or terrain was imminent, and immediate action was taken at that point. Assuming that the E–drop system was functional, a critical and missing element of the sequence of events was that the entire retardant load was not jettisoned. Given that retardant was not deposited on the trees that were struck, a full or partial retardant drop may not have changed the sequence of events. However, in an emergency, it would be expected that the full load would have been jettisoned. The fact that it was not is worthy of analysis.

Factors that could have influenced an attempt to execute an E–drop include the following:

  • A visual illusion could have precluded timely recognition, or accurate assessment, of the aircraft’s flight path relative to the terrain thereby obviating the need to execute an E–drop.
  • The FO training did not include an E–drop exercise. Since the FO was new to the job and the aircraft, he likely relied heavily upon the captain’s instructions. Given the direction in the company’s manuals regarding load jettisons, the FO probably would not have executed an E–dropon his own initiative under any circumstance. Company procedures regarding unwarranted jettison of the load were quite specific in pointing out the following:
    • An irreversible action or guarded switch will be confirmed prior to operation.
    • Jettison action will require the captain’s initiation.
    • The E–drop selector should only be used if the captain’s drop button fails.
  • In most cases the E–drop selector would be operated by the FO but, in accordance with SOP, that would still require a verbal command by the captain and recognition by the FO of the, likely unanticipated, command.
  • To execute an E–drop, the location of the E–drop selector required a significant diversion of attention by both pilots to identify and confirm it among other guarded switches. This procedure may have consumed more time and attention than was available.

Since the recommended maintenance inspection task to perform a functional check of the E–drop system may not be performed due to environmental concerns, and there is no requirement for flight crews to test the E–drop system in lieu of the maintenance ground check, a functional test of this emergency system may not occur to confirm its continued operation once the fire season begins.

Findings as to causes and contributing factors

  1. It could not be determined to what extent the initial collision with trees caused damage to the aircraft which may have affected its controllability.
  2. Visual illusion may have precluded recognition, or an accurate assessment, of the flight path profile in sufficient time to avoid the trees on rising terrain.
  3. Visual illusion may have contributed to the development of a low energy condition which impaired the aircraft performance when overshoot action was initiated.
  4. The aircraft entered an aerodynamic stall and spin from which recovery was not possible at such a low altitude.

Findings as to risk

  1. Visual illusions give false impressions or misconceptions of actual conditions. Unrecognized and uncorrected spatial disorientation, caused by illusions, carries a high risk of incident or accident.
  2. Flight operations outside the approved weight and balance envelope increase the risk of unanticipated aircraft behaviour.
  3. The recommended maintenance check of the emergency drop (E–drop) system may not be performed and there is no requirement for flight crews to test the E–drop system, thereby increasing the risk that an unserviceable system will go undetected.
  4. The location of the E–drop selector requires crews to divert significant time and attention to identify and confirm the correct switch before operating it. This increases the risk of collision with terrain while attention is distracted.
  5. The location of the angle–of–attack indicator on the instrument panel makes it difficult to see from the right seat, reducing its effectiveness.
  6. When cockpit recordings are not available to an investigation, this may preclude the identification and communication of safety deficiencies to advance transportation safety.

Other finding

  1. Although the aircraft was equipped with an automatic position reporting system, which was invaluable, the reporting frequency of 2 minutes was insufficient to capture all of the data critical to the analysis of the accident.

Safety action taken

Conair Group Inc.

Since the accident, Conair has taken further action to mitigate the risks of recurrence.

  1. The glare shield over the flight instrument panel in the Convair 580 has been modified to improve both pilots’ view of the top row of flight instruments, which include the airspeed indicators and the angle–of–attack indicator.
  2. A project has been initiated to change the emergency drop selector from a guarded toggle switch to a large push–button type switch and relocate it to the middle of the glare shield, in full view and within reach of both pilots.
  3. A project is underway to modify the existing load release button on the left–hand control wheel to include a safety function which will jettison the entire retardant load if the button is depressed 5 times within 3 seconds.
  4. The Conair pilot training program is being amended to incorporate more emphasis on emergency drop procedures.
  5. Conair is developing a stall–g–speed (SgS) 8 system for air tanker operations. This system will be initially installed on the Lockheed L–188 Electra air tanker.

B.C. Ministry of Forest Lands and Natural Resource Operations

The B.C. Ministry of Forest Lands and Natural Resource Operations (MFLNRO) staff is in the process of clarifying and communicating procedures that allow air tanker operators to conduct ground testing of E–dump systems as required by the operators on MFLNRO tanker bases.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on  06 March 2012.


  1. The standard circuit is comprised of 4 segments: crosswind leg, downwind leg, base leg and the final leg. ↑
  2. Manoeuvre of an airplane in which one wing is stalled while the other wing continues to produce lift. The nose drops, and the airplane descends slowly, with the wing producing lift pulling it around in a spiral path. Dictionary of Aeronautical Terms, 3rd edition. Dale Crane. ↑
  3. All times arePacific Daylight Time (Coordinated Universal Time minus 7 hours). ↑
  4. Pilot flying. ↑
  5. Pilot not flying. ↑
  6. Refers to the Conair CV–580 maintenance “A” inspection. ↑
  7. Department of the Army (US), Field Manual No. 3–04.301 (1–301) Chapter 9 – Spatial Disorientation http://www.cavalrypilot.com/pdfpubs/fm3_04x301.pdf. ↑
  8. SgS defines a safety flight envelope for “low speed warning”, “vertical acceleration (g) warning” and “overspeed warning”. This system will provide flight crews with trend information relating airspeed, angle–of–attack, and “g” load information in a visual display with audio warnings and a stick–shaker function. ↑

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Aviation Reports – 2011 – A11F0012

| Transportation Safety Board Reports | April 16, 2012

Transportation Safety Board of Canada

Aviation Reports – 2011 - A11F0012

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Pitch Excursion
Air Canada
Boeing 767–333, C–GHLQ
North Atlantic Ocean, 55°00N 029°00W
14 January 2011

Report Number A11F0012

Synopsis

The Air Canada Boeing 767–333 (registration C–GHLQ, serial number 30846) was operating as flight ACA878 from Toronto, Ontario, to Zurich, Switzerland. Approximately halfway across the Atlantic, during the hours of darkness, the aircraft experienced a 46–second pitch excursion. This resulted in an altitude deviation of minus 400 feet to plus 400 feet from the assigned altitude of 35 000 feet above sea level. Fourteen passengers and 2 flight attendants were injured. The seatbelt sign had been selected “on” approximately 40 minutes prior to the pitch excursion. The flight continued to destination whereupon 7 passengers were sent to hospital and were later released.

Other factual information

History of flight

Air Canada flight 878 (ACA878) departed Toronto/Lester B. Pearson International Airport, Ontario (CYYZ), on 13 January 2011 at 2138 1 with 95 passengers, 6 flight attendants and 2 flight crew. The planned routing was north of the North Atlantic Organized Track System (OTS) on a random track 2 in order to avoid forecast turbulence associated with the jet stream. The captain had elected to use the centre line option as per the strategic lateral offset procedures 3 (SLOP) in the Air Canada Flight Operations Manual (FOM).

Controlled rest—Air Canada FOM, Section 2.9.10 —Alertness Management, describes controlled rest as an operational fatigue countermeasure that improves on–the–job performance and alertness when compared to non–countermeasure conditions. Controlled rest uses strategic napping on the flight deck to improve crew alertness during critical phases of flight. The rest periods are a maximum of 40 minutes in length (periods to be reviewed prior to resting) and must be completed 30 minutes prior to the top of descent. The In–Charge Flight Attendant must be advised that controlled rest will be taking place and instructed to call the flight deck at a specific time. Upon conclusion of the rest period, unless required due to an abnormal or emergency situation, the awakened pilot should be provided at least 15 minutes without any flight duties to become fully awake before resuming normal duties. An operational briefing shall follow.

At 0040, the first officer (FO) expressed the need for a rest. The captain agreed and the FO commenced a controlled rest. The in–charge flight attendant (IC) was not advised.

Shortly after the start of the controlled rest, the captain increased the lighting on the flight deck to review aircraft manuals in preparation for upcoming training. This type of reading was in accordance with Air Canada standard operating procedures.

At 0118, the captain turned on the seatbelt sign in anticipation of the turbulence forecast for the area. An announcement by the IC was made to remind passengers that the seatbelt sign was now on and that they were to remain seated with their seatbelts secured. 4 Up to this point, there had been no turbulence; after the event, it was light to nil.

In response to the seatbelt sign being turned on, the flight attendants made a visual inspection of the passengers for compliance; the majority were asleep. Many of the passengers in economy were lying down across the centre 3 seats. Business class featured the lay–flat seats with seatbelts equipped with air bags, and the majority of those passengers were also lying down and appeared to be asleep.

At 0155, the captain made a mandatory position report with the Shanwick Oceanic control centre. This aroused the FO. The FO had rested for 75 minutes but reported not feeling altogether well. Coincidentally, an opposite–direction United States Air Force Boeing C–17 at 34 000 feet appeared as a traffic alert and collision avoidance system (TCAS) target on the navigational display (ND). The captain apprised the FO of this traffic.

Over the next minute or so, the captain adjusted the map scale on the ND in order to view the TCAS target 5 and occasionally looked out the forward windscreen to acquire the aircraft visually. The FO initially mistook the planet Venus for an aircraft but the captain advised again that the target was at the 12 o’clock position and 1000 feet below. The captain of ACA878 and the oncoming aircraft crew flashed their landing lights. The FO continued to scan visually for the aircraft. When the FO saw the oncoming aircraft, the FO interpreted its position as being above and descending towards them. The FO reacted to the perceived imminent collision by pushing forward on the control column. The captain, who was monitoring TCAS target on the ND, observed the control column moving forward and the altimeter beginning to show a decrease in altitude. The captain immediately disconnected the autopilot and pulled back on the control column to regain altitude. It was at this time the oncoming aircraft passed beneath ACA878. The TCAS did not produce a traffic or resolution advisory.

During the pitch excursion, the aircraft pitch changed from the cruise attitude of 2 degrees nose up, to 6 degrees nose down followed by a return to 2 degrees nose up. The vertical acceleration forces (g) went to −0.5 g to +2.0 g in 5 seconds. Computed airspeed increased 7 knots then decreased 14 knots before recovering to cruise speed with the aircraft’s altitude decreasing to 34 600 feet increasing to 35 400 feet and finally recovering to 35 000 feet.

No one in business class had been displaced and/or injured during the event. When the IC walked into economy, it became apparent that there were passengers and crew injured from contacting cabin fixtures and armrests and the IC began to arrange for first aid. Two medical professionals identified themselves and provided assistance to the cabin crew. Once an assessment of injuries had been made, the IC advised the captain and a satellite phone link was established with Air Canada flight operations to advise of the situation and to establish a phone link with a physician trained in assessing injuries and illnesses encountered during flight. After coordinating through Air Canada dispatch, and speaking directly to the physician, the captain directed the IC to speak directly with those injured. Based on the information received from the injured, the physician’s assessment, the enroute weather and a number of other factors, the decision was made that it was acceptable to continue to destination. Medical services were readied in Zurich for the arrival of ACA878.

The total number of passengers who were not seated with their seatbelts fastened is unknown. None of the passengers in business class was injured. The 14 passengers who were seen for their injuries were all located in economy in various locations (Appendix A). One injured flight attendant was in the rear galley, the other in a lavatory. All injuries were of the soft tissue variety, and a few of the injured sustained lacerations.

A pilot dead–heading to Zurich (to serve as relief pilot for the return flight) was on the flight. After the captain was informed of the injuries, a request was made to have this pilot sit on the flight deck to monitor the flight and assist as required. The remainder of the flight was uneventful. The flight was met by medical help upon arrival at Zurich. Within 20 minutes, all injuries were assessed and passengers were either released or sent to hospital for further observation.

Flight crew

Records indicate that the flight crew were certified and qualified for the flight in accordance with existing regulations. The captain had over 30 years of experience at Air Canada and 14 800 hours total flight time including just over 400 hours pilot–in–command on type since qualifying as captain on the Boeing 767 in the spring of 2010. The FO had 24 years in aviation, the last 14 years at Air Canada, with 12 000 hours total flight time including approximately 2 000 hours on the Boeing 767 in the previous 4 years.

It was normal for both the captain and the FO to sleep at night. During the days leading up to the occurrence, the captain had not been working but had had a cold so slept longer than usual (12 hours instead of 10 hours). On the day of departure, the captain rose at approximately 0800 feeling recovered. The captain then performed a 6.5–hour commute from Florida to Toronto via aircraft. The captain obtained approximately 90 minutes of prone rest in the flight operations pilot rest facility before reporting for duty feeling well rested. This facility is a quiet room equipped with beds to permit prone rest.

Before he had children, the FO‘s normally slept 8 hours per night. After having children, the FO normally slept approximately 6 to 7 hours per night, between 2300 and 0600, which could often be interrupted when the children required care. Often, the FO would take a nap early in the afternoon for an hour in an attempt to make up for lost sleep. The FO followed a normal sleep pattern during the 2 non–working days prior to the occurrence. The night before the occurrence, the FO was able to obtain nearly 8 hours of rest with some child care interruptions before waking at approximately 0600. The FO took a 2–hour nap in the afternoon before reporting for duty feeling well rested.

Both crew members checked in at the required time of 1935 and the aircraft pushed back at 2109. ACA878 landed in Zurich at 0505 and was at the gate at 0509 for a total flight time of 8 hours and 4 minutes, which was 9 minutes longer than scheduled.

Evening–departure flights to european destinations: fatigue issues

Fatigue reduces performance levels and increases the desire to obtain sleep. This effect is magnified during circadian lows 6, which are encountered by people who normally sleep at night and work during the day (diurnal). For example, North American pilots flying eastward at night across the Atlantic experience circadian lows that magnify performance decrements and increase desire to sleep.

Night flights from North America to Europe have an inherent risk of fatigue for North American–based pilots. Most of these pilots fly a small number of night–time legs per month and revert to sleeping at night when not working. The circadian system of pilots who fly only a small number of night–time legs will not adapt to working at night 7, and these pilots are likely to display performance decrements during the night–time legs 8 in spite of any countermeasures.

To counter fatigue, some pilots will try to nap before a night–time leg. While this can be helpful in some cases, it cannot prevent fatigue in all pilots. Moreover, it is not always possible to obtain an adequate amount of good quality sleep during the day 9 and, coupled with a small number of night–time legs, performance decrements will persist.

In addition, these types of flights are characterized by long periods of darkness with few operational demands while mid–Atlantic, creating inherently soporific conditions 10.  It is not until the flight approaches the coast of Europe at dawn that pilots experience reduced sleepiness as the daylight and circadian rhythms start to alleviate some of the fatigue. Nonetheless, the high workload requirements of approach and landing have to be borne at a time when there is a significant risk of pilot fatigue.

Pilots must develop strategies in advance to manage their fatigue effectively. Planning related to trans–Atlantic flights typically takes place during the early evening when diurnal pilots experience a circadian high. In such cases it may be difficult for pilots to assess their readiness to undertake the entire flight based on their subjective assessment of their alertness or sleepiness immediately prior to the flight and instead rely on their personal assessment of the adequacy of their pre–flight sleep regime.

Fatigue risk management

Transport Canada outlines a series of defences in its Fatigue Risk Management System (FRMS) for the Canadian aviation industry. 11 While not targeted specifically to flight operations, it provides a useful benchmark from which a review of fatigue management at Air Canada can be made. This is similar to the FRMS framework that was under development at the time of the occurrence by ICAO for flight operations. 12 The defences include

  • creating sufficient opportunity for sleep (Canadian Aviation Regulations, crew scheduling, etc.);
  • obtaining sufficient sleep (employee actions, on–going assessment);
  • monitoring for fatigue while on duty (symptom checklists, self–reporting);
  • fatigue based error mitigation (for instance caffeine, controlled rest, relief pilots, error reporting);
  • fatigue based occurrence analysis (safety management system [SMS]–based incident and accident analysis); and
  • fatigue training and awareness program.

Some of these are explored below.

In an effort to address fatigue risks, the Canadian Aviation Regulation Advisory Council formed a Flight Crew Fatigue Management Working Group in September 2010 to make recommendations regarding the flight time and duty time limitations and rest period regulations based on the science that underpins the FRMS. Fourteen meetings were held; the last was in December 2011. Transport Canada summarized the process so far:

The Co–chairs have begun the process of writing the report of the working group. The report will summarize the science, harmonization, and operational experience associated with each issue discussed. It will include recommendations from the working group, where consensus was found, and recommendations from the Co–chairs where there was no consensus of the working group. One area of consensus was the effect of circadian rhythms on the length of the flight duty period. The longest duration flight duty period available would start from between 0700 and 1200, and the shortest duration flight duty period available would start from between 2300 and 0430 am [sic] – accounting for the window of circadian low and the generally reduced performance during this period.

Crew scheduling at Air Canada

From a carrier’s point of view, crew scheduling involves the need to ensure that all flights have qualified crews while minimizing labour costs and complying with a wide variety of constraints governed by safety regulations and labour contracts. For crews under bid systems such as those at Air Canada, earnings and convenience also play a role in crew scheduling.

While crew scheduling aims to address the employer’s role to provide work conditions that allow employees to accrue sufficient rest, employees are obligated to make appropriate use of that rest time and report fit for duty. 13

Neither the Canadian Aviation Regulations nor Air Canada makes specific accommodations to account for the particular risks associated with operating overnight flights during a circadian low.

Air Canada, with its pilot association, has a mechanism to review crew pairings (flights) that pilots may consider to be onerous. The occurrence flight, at the time of the occurrence, had not been brought forward as a concern under this mechanism.

Monitoring for fatigue

The aim of fatigue monitoring is to identify a pilot who appears to be in a fatigued state and take appropriate actions before an error occurs. While Air Canada provides information concerning the causes and effects of fatigue, it does not provide procedures or information concerning the identification of fatigued colleagues through observation of symptoms. Currently there is no “fit to fly” checklist 14 to enable employees to self–monitor or monitor others in order to identify effectively crew members who may not be sufficiently alert to perform their duties.

Fatigue–based error mitigation

Air Canada training on fatigue management outlines several strategies for mitigating fatigue in order to reduce the likelihood of errors, such as exercise, social interaction and caffeine. Two specific strategies— controlled rest and the use of relief pilots—are described in more detail below.

Controlled rest

Controlled rest is the strategic use of short naps on the flight deck to improve crew alertness during critical phases of flight. Research has shown that this improves on–the–job performance compared with non–countermeasure conditions. 15 This approach has been adopted by 17 air carriers in Canada and several airlines around the world such as British Airways, Qantas, Air New Zealand and Emirates. The approach was adopted by Transport Canada in 1996 and is specified in CAR 700.23 and Commercial Air Services Standards (CASS) 720.23. Authorization for Air Canada to conduct controlled rest was granted by Transport Canada on 13 June 2005.

At Air Canada, the in–charge flight attendant must be advised that controlled rest will be taking place and must be instructed to call the flight deck at a specific time 16. The rest periods are a maximum of 40 minutes in length and must be completed 30 minutes prior to the commencement of descent.

Upon conclusion of the rest period, the awakened pilot should be provided at least 15 minutes without any flight duties to become fully awake before resuming normal duties, unless required to do so due to an abnormal or emergency situation. Following the 15–minute wakening period, an operational briefing must be given.

This is designed to ensure that the rest is taken in a manner that minimizes risks to the flight. This includes

  • ensuring that rest is only undertaken during portions of the flight that are anticipated to be low risk and do not require actions by the resting pilot;
  • the period of sleep is not so long that the pilot is likely to suffer from sleep inertia;
  • the cabin attendant enters the cockpit after the rest period to ensure that both pilots are not asleep; and
  • sufficient time is provided for the wakening pilot to recover from the sleep.

Relief pilot

Transport Canada recognizes a relief pilot as a pilot who is fully trained to the successful completion of a pilot proficiency check on the aircraft type and utilized solely for the purpose of providing flight relief for the captain or FO in order to extend flight deck duty times. Transport Canada issues individual type ratings for relief pilots for aircraft that require a minimum of 2 flight crew. These type ratings come with a restriction indicating that a relief pilot may relieve a member of the flight crew only while the aircraft is in cruise. The relief pilot must have a Commercial or Airline Transport Pilot Licence with a Group 1 instrument rating.

At Air Canada, relief pilots are trained to the FO standard and possess Airline Transport Pilot Licences. They are issued the aircraft type rating without the relief pilot restriction.

Relief pilots are used at Air Canada according to the terms of the collective agreement. In the case of ACA878, a relief pilot is not required where the maximum flight time is 9 hours and the duty day maximum is 11 hours. In this occurrence, the scheduled flight time for ACA878 was 7 hours 55 minutes and a duty day of 9 hours 25 minutes. For the return flight, ACA879, the scheduled flight time was 9 hours 5 minutes and a duty day of 10 hours 35 minutes. In that instance the flight time exceeded 9 hours and a relief pilot was required to work the flight. To comply with this agreement, a relief pilot dead–headed on flight ACA878 in order to work the return flight ACA879.

By using a relief pilot, flight crews may obtain a higher quality of rest by removing themselves from the flight deck and obtaining longer periods of rest time.

Reporting and analysing fatigue–based errors

At Air Canada, there are several methods through which flight crew can communicate various concerns during flight operations. For safety of flight issues, the Aviation Safety Report (ASR) is used to capture occurrences for analysis by the flight safety department under Air Canada’s SMS; the ASR does not specifically identify fatigue on the form. A Flight Crew Report (FCR) is used to address administrative and contractual issues. In addition to these reporting streams, the Air Canada Pilots Association (ACPA) has a form specific to capturing fatigue–related issues.

In the calendar year 2010, the Air Canada SMS database system contained no ASRs related to fatigue; in particular, there were none for the eastbound European flights that departed in the evening. Conversely, the FCR system contained 5 reports pertaining to the fatigue issues on these types of flights and 4 of those reports questioned the rationale for not having a relief pilot on the eastbound flights.

In November 2009 Air Canada’s SMS was assessed by Transport Canada. In that assessment Transport Canada had moderate findings 17 for the SMS elements of reactive and proactive reporting processes for safety oversight. Air Canada’s corrective action plan was filed in September 2010. Transport Canada accepted that plan on 20 July 2011 with implementation to be completed by 31 July 2012.

Fatigue risk management training at Air Canada

Fatigue risk management training is a foundation for many of the defences against fatigue. It provides employees with knowledge of how to avoid, mitigate and report fatigue issues. CASS 720.23 – Controlled Rest on the Flight Deckrequires that every crew member who participates in the controlled rest on the flight deck program shall have received training in the program as well as training in the general principles of fatigue and fatigue countermeasures. In the Air Canada Flight Operations Manual, the training requirement associated with controlled rest is that: “prior to practising controlled rest the pilots shall be familiar with the contents of the relevant Flight Operations Manual Bulletin.” 18

All pilots at Air Canada are required to attend annual recurrent training (ART) as part of the Air Canada Continuing Qualification program. The requirements of CASS 725.124 are met by a 6–year training matrix that is reviewed by Air Canada and approved by Transport Canada on an annual basis. Requirements under CASS 725.124 do not include the requirements of CASS 720.23 and as such, Air Canada had included a separate module on controlled rest in 2005, 2006 and 2010. Controlled rest is also covered in initial training for newly hired pilots.

Both the captain and FO were on year 3 of the ART program which featured the module on fatigue risk management. The captain attended ART on 25 June 2010 and the FO on 15 September 2010. This unit was approximately 30 minutes in length and reviewed the science behind fatigue, fatigue mitigation options for flight crew while away from work and at work. The training briefly covered the stages of sleep and the effects of sleep inertia.

The approach taken to training for controlled rest was to read the controlled rest procedure to the trainees. Transport Canada’s expectation concerning training for controlled rest was based on Guidance Material S740.23 which refers to the NASA Ames Fatigue Countermeasures Program. This program provides a module in alertness management in flight operations. In this module’s introduction it states that the information is intended to be offered as a live presentation by a trained individual to ensure an interactive format that would promote discussion.

When new material is provided on a topic that differs only slightly from what is known but is critical, the difference must be emphasized so that it will be retained. 19 In addition, unless they are told why the procedures are taught, it is common for workers either to default to what they know or to exceed the limits set in the procedures until they encounter actual safety problems. 20

Air Canada’s internal flight safety magazine, Flight Line, featured an article on sleep inertia in the fall/winter 2010 issue. Neither the captain nor FO had read the article prior to the occurrence.

Pilot knowledge of fatigue and controlled rest

The occurrence pilots and several line pilots at Air Canada were interviewed in order to assess their knowledge of fatigue mitigation measures and in particular their knowledge of controlled rest. General knowledge about how to manage their rest for flights was good but there were specific gaps including their knowledge of how disturbances to sleep, such as those caused by caring for children, waking periods during the night or snoring can affect the quality of sleep and subsequently increase the risk of fatigue. They were unsure how to assess whether symptoms of fatigue in themselves or a colleague might indicate being unfit to fly, but they did have a good understanding of methods they could use to mitigate fatigue during flight.

All of the pilots understood that they were required to call cabin crew prior to taking a controlled rest, but they tended to rely on their own assessment of the sleepiness of the non–resting pilot in order to decide whether the cabin crew needed to be told that rest was being taken. Since pilots take controlled rest at times when they are most sleepy, which is likely to be at a similar time to the other pilot due to the circadian rhythm of fatigue, there is a high risk of night–time controlled rest resulting in both pilots falling asleep. 21 One of the reasons they were reluctant to inform cabin crew was that they knew cabin crew were not entitled to controlled rest themselves. They did not realize that by not informing the cabin crew of the controlled rest they were creating the possibility of the resting pilot being disturbed.

There was considerable misunderstanding about the reason why controlled rest was limited to 40 minutes. Some pilots believed that 20–40 minutes could not provide appreciable benefits and believed that what was really required was a significant sleeping period—90 to 120 minutes. Some were unaware that by sleeping longer than 40 minutes there was a high risk of entering slow–wave sleep and increasing the severity of sleep inertia.

Their knowledge of sleep inertia was low. They were aware of the term but were not aware how significantly impaired a recently awakened pilot could be. They believed that the recuperation period after a rest was for the pilot to become apprised of the current state of the flight operations, rather than to come back to full alertness.

Sleep inertia

Sleep inertia 22 refers to the post–sleep performance decrements that occur immediately after awakening. Sleep inertia is a transient physiological state characterized by confusion, disorientation, low arousal, and deficits in various types of cognitive and motor performance. 23 Although the duration of sleep inertia is usually short, from 1 to 15 minutes 24, some deleterious effects can last 30 minutes 25 or longer. 26

Research indicates that the duration and severity of sleep inertia can be worse

  • if naps are longer 27;
  • if naps occur during the circadian core body temperature trough or circadian low 28 (normally in the middle of the night for a diurnally–oriented person);
  • when the person is sleep deprived or has been awake for an extended period 29; and the nap contains or ends with slow–wave sleep. 30

One of the detrimental effects of sleep inertia is a decrease in cognitive processing speed. 31 For example, it takes longer than normal for a person experiencing sleep inertia to filter out incongruous visual information. 32

Given that a decrease in cognitive processing speed, confusion and disorientation are characteristic performance decrements of sleep inertia and that it also results in a propensity for visual distraction and reduced ability to filter out irrelevant visual information, 33 it is important to allow adequate recovery time after a nap to offset sleep inertia’s effects.

It is also important to control the amount of sleep during controlled rest. One study 34 showed that the best reaction times were demonstrated after naps of only 20 minutes compared to naps of 50 and 80 minutes. This may be a direct result of awakening from slow–wave sleep in the longer nap condition. 35

Assessing flight paths of opposite–direction aircraft at night

The assessment of relative position at night is difficult: there are few external cues by which the position and motion of objects can be assessed. Visual cues are further reduced if the cockpit lights are turned on full. In the case of assessing whether an oncoming aircraft at similar altitude will pass above or below, there is no horizon by which to assess the relative motion. When the aircraft is distant it appears as a single point of light with no motion relative to the observer. Based on tests conducted in an Air Canada B767 simulator, no distinct motion up or down the field of view of an oncoming aircraft was detectable until the aircraft was 15 seconds apart at a closure speed of 900 knots. An oncoming higher aircraft then moves up the visual field and an oncoming lower aircraft moves down the visual field. There are no known illusions where a person can perceive an oncoming object as moving contrary to the actual path.

C–GHLQ Boeing 767–333

Records indicate that the aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. Nothing was found to indicate that there was any system malfunction prior to or during the flight.

The aircraft was equipped with a cockpit voice recorder (CVR) that had a 2–hour recording capacity and a digital flight data recorder (DFDR) with a 25–hour recording capacity. The event was captured on the DFDR but not on the CVR. The aircraft was just over 3 hours from arrival in Zurich when the pitch excursion occurred; therefore, the event was overwritten on the CVR.

At the time of the occurrence, the aircraft’s autopilot flight director system was engaged in the normal single–channel mode for cruise flight. A crew member can manipulate the controls when the autopilot is engaged: the engaged autopilot servo will cam–out and the flight crew will have direct control of the primary flight control surfaces. A push or pull force of 24 pounds is required for this action to occur on the elevator servo. A push force of 80 pounds was input by the FO during the event.

The following TSB laboratory report was completed:

LP009/2011 FDR Analysis

This report is available upon request from the Transportation Safety Board of Canada.

Analysis

Sleep inertia

The FO felt fit for flight at the time of reporting for duty at 1935, which likely coincided with a circadian high. 36 However, the interrupted sleep obtained in the 24 hours immediately preceding the flight increased the likelihood the FO would feel fatigued and need rest during the overnight eastbound flight, particularly as a circadian low was reached. The FO fell completely asleep during the controlled rest period which also indicates the FO‘s level of fatigue.

With a view to providing a substantial rest, the captain allowed the FO to rest beyond the 40–minute maximum set as a defence against entering slow–wave sleep; the 75–minute rest that ensued increased the probability of entering slow–wave sleep. The severity and duration of sleep inertia are more likely to be worse if a person is awakened from slow–wave sleep, especially if the rest occurs at a circadian low and when the person is fatigued. Given the consistency between the conditions that worsen sleep inertia and the FO‘s sleep and controlled rest, and the observation that the FO felt unwell when awakened, it is likely that the FO was suffering from high levels of sleep inertia.

Action taken following identification of the oncoming aircraft

The captain followed standard procedure after the identification of the oncoming aircraft as a TCAS target on the ND. The captain sought the aircraft visually—which, at this point, appeared as a single point of light approximately straight ahead of the aircraft—and verified the target. This task was made more difficult by the cockpit lights being on full, causing reflections in the cockpit glass and hindering the view outside the aircraft. At about this time the FO awoke. To avoid the FO being startled, the captain twice pointed out the relative position of the oncoming aircraft to the FO. This occurred approximately 1 minute after the FO had woken and was most likely suffering from the strong effects of sleep inertia. The FO was not in a state to effectively assimilate the information from both the instruments and from outside the aircraft or effectively provide an appropriate response. Despite having been trained to interpret TCAS targets and react to them, the FO was drawn to rely on immediate perceptual information. Under the effects of sleep inertia, the FO was likely confused and disoriented and perceived the aircraft on an imminent collision course. Consequently, the FO pushed forward on the control column to avoid the collision. The FO quickly realized the error because the traffic appeared to be moving down in the visual field, which did not make sense.By that time, the captain had reversed the control movement to return the aircraft to the previous altitude.

By identifying the oncoming aircraft, the captain engaged the FO before the effects of sleep inertia had worn off. As a consequence, the FO did not form an effective response to the situation.

Training for controlled rest procedures at Air Canada

Several deviations from Air Canada controlled rest SOP occurred. They included:

  • not advising the cabin crew of the intention to rest;
  • not agreeing in advance on an end time of 40 minutes;
  • not stopping the rest at 40 minutes; and
  • not providing recovery time after the rest.

Each of these actions was consistent with common misunderstandings among Air Canada pilots.

The procedure for controlled rest provides a means to manage rest and avoid unsafe consequences. For instance, if sleep goes beyond 40 minutes, there is an increased risk of slow–wave sleep, which will likely be followed by longer and more severe sleep inertia. Sleep inertia will happen after any nap. It is particularly important, however, that naps taken during the night on a flight from North America to Europe conform to the procedure because these are likely to occur when other factors, such as the circadian low, are likely to exacerbate any sleep inertia.

The training provided by Air Canada on controlled rest was limited to repeating the procedure in the FOM to the trainees, and did not explain or emphasize why the boundaries of the procedure are critical to safety. The safety publication did describe some of these issues but this form of training does not reliably lead to the level of training required.

Although training was provided on controlled rest and the topic was covered in a recent Air Canada flight safety magazine, this was insufficient to ensure that pilots fully understood and carried out the controlled rest procedures.

Air Canada analysis of fatigue reports

At Air Canada there are several methods in which flight crew can identify fatigue–related issues during flight operations: Aviation Safety Reports, Flight Crew Reports (FCR) and specific fatigue reporting forms distributed by ACPA. Such a wide range of options allows a situation where safety issues related to fatigue may be reported in one system but not analyzed because it does not appear in Air Canada’s SMS. The TC–recognized SMS reporting system at Air Canada may not be effective as several reporting systems are being used to report fatigue–related safety issues.

Passenger safety

Passengers had been briefed to always wear their seatbelts when seated. Although the seatbelt sign was on and an announcement was made regarding potential turbulence, several passengers were injured during the event because they were not wearing their seatbelt. Some passengers may not be aware of the inherent risks in not wearing a seatbelt at all times when seated.

Use of relief pilot

Night flights from North America to Europe have an inherent risk of fatigue for North American–based pilots. Research to date has not identified a level of alertness required in order to ensure the safety of operations at the end of such a flight, particularly during the heavy workload period of approach and landing. While controlled rest mitigates fatigue to some extent, studies have not been able to show whether it is sufficient in order to fully mitigate fatigue during this type of flight. More effective rest can be obtained with the use of a relief pilot on eastbound flights.

Findings as to causes and contributing factors

  1. The interrupted sleep obtained by the first officer prior to the flight increased the likelihood that rest would be needed during the overnight eastbound flight.
  2. The first officer slept for approximately 75 minutes which likely placed the first officer into slow–wave sleep and induced longer and more severe sleep inertia.
  3. The first officer was experiencing a circadian low due to the time of day and fatigue due to interrupted sleep which increased the propensity for sleep and subsequently worsened the sleep inertia.
  4. By identifying the oncoming aircraft, the captain engaged the first officer (FO) before the effects of sleep inertia had worn off.
  5. Under the effects of sleep inertia, the first officer perceived the oncoming aircraft to be on a collision course and pushed forward on the control column.
  6. The frequency of training and depth of the training material on fatigue risk management to which the flight crew were exposed were such that the risks associated with fatigue were not adequately understood and procedures for conducting controlled rest were not followed by the flight crew.
  7. Although the seatbelt sign was on and an announcement about potential turbulence was made, several passengers were injured during the event because they were not wearing their seatbelt.

Findings as to risk

  1. North American–based pilots flying eastbound at night towards Europe are at increased risk of fatigue–related performance decrements.
  2. The use of multiple safety occurrence reporting systems may result in some safety issues not being properly identified and analyzed.
  3. Some passengers may not be aware of the inherent risks in not wearing a seatbelt at all times when seated.

Other finding

  1. As the aircraft cockpit voice recorder (CVR) was only capable of recording for 2 hours, the event was overwritten.

Safety action taken

Air Canada

On 2 March 2011, Air Canada issued FOM Bulletin 13–11 emphasizing that flight crew must adhere to all components of the SOP in order for the controlled rest to be implemented safely. The bulletin emphasized the requirement to notify the applicable flight attendant and to arrange for a call from the flight attendant no later than 45 minutes from the time of briefing.

On 2 March 2011, Air Canada issued FOM Bulletin 14–11 which emphasized the benefits of using strategic lateral offset procedures (SLOP) and to offset by 1 or 2 nm at all times including random tracks unless the course places the aircraft on a less desirable track.

On 23 March 2011, Air Canada Flight Operations issued bulletin 28–11 identifying a Pairing Evaluation and Assessment Committee (PEAC) data collection exercise on the Toronto–Zurich route in an effort to understand the alertness levels of crews on these flights. This committee has both company and association representation.

Air Canada Cabin Safety issued a bulletin to all in–flight service personnel that cabin crew are an important part of the SOP for controlled rest on the flight deck and emphasized the flight deck briefing that is required and the call to the flight deck when 45 minutes have elapsed.

Air Canada Pilots Association (ACPA) – Technical and safety division

On 1 March 2011, ACPA issued newsletter No. 3, a Crew Flash Alert from the Technical and Safety Division, regarding the collection of data on flights that occur in the window of circadian low. This 60–day collection of data commenced with the Toronto–Zurich–Toronto operation but may expand to other similar routes. Pilots were asked to fill out the ACPA fatigue form prior to top of descent to capture the subjective rating of their alertness/fatigue. This survey is in addition to the data collection efforts of the Flight Standards and Quality department.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on  29 February 2012.

Appendix A – Seating Diagram and Location of the Injured

Appendix A - Seating Diagram and Location of the Injured


  1. All times Eastern Standard Time (Coordinated Universal Time minus 5 hours). ↑
  2. Transport Canada, Aeronautical Information Manual, section RAC 11.6.1 advises that non–OTS tracks be great circle tracks joining successive significant points. For flights south of 70°N, such as for flight ACA878, the significant points are defined by the intersection of half or a whole degree of latitude at each 10 degrees of longitude. The distance between significant points shall not exceed 1 hour of flight time. ↑
  3. SLOP is recommended to reduce the exposure to turbulence from aircraft on the same track and to increase safety margins should another aircraft deviate from its assigned altitude. There are 3 options: centre line, 1 nautical mile (nm) right and 2 nm right. An ATC clearance is not required to SLOP when flying in the Gander or Shanwick Oceanic sectors. ↑
  4. This was in addition to the initial safety briefing where passengers are advised to keep their seatbelts fastened whenever seated. ↑
  5. TCAS targets show at the 30 nm range. With the ND set at 320 nm, as it was in this case, the TCAS target would appear on top of the aircraft symbol at the bottom of the ND. It is Air Canada standard operating procedures (SOP) to reduce the range to ensure a clear depiction of the TCAS target relevant to the aircraft. ↑
  6. Circadian lows are periods of high fatigue and poor performance. The highest levels of fatigue and worst performance occur when circadian rhythms dictate sleep. For a diurnal person this is during the night. See for examples: Härmä, M., Sallinen, M., Ranta, R., Mutanen, P., & Müller, K. (2002). The effect of an irregular shift system on sleepiness at work in train drivers and railway traffic controllers. Journal of Sleep Research, 11, 141 – 151; Ingre, M., Kecklund, G., Åkerstedt, T., & Kecklund, L. (2004). Variation in sleepiness during early morning shifts: A mixed model approach to an experimental field study of train drivers. Chronobiology International, 21(6), 973–990; Gupta, S. & Pati, A. (1994). Desynchronization of circadian rhythms in a group of shift working nurses: Effects of pattern of shift rotation. Journal of Human Ergology, 23(2), 121–131; Tilley, A., Wilkinson, R., Warren, P., Watson, B., & Drud, M. (1982). The sleep and performance of shift workers, Human Factors, 24(6), 629–641. ↑
  7. In general, researchers have found that the adjustment of the human circadian system resulting from changes to sleep–wake pattern occurs at a rate of 1 to 1.5 hours per day. Adjusting from being awake during the day to being awake at night, a 12 hour difference, could take between 12 and 18 days for complete adjustment to take place and optimum performance to return. Flying one night shift will not result in adequate circadian adjustment and pilot performance will continue to be affected by circadian lows during night flying (Klein, K. & Wegmann, H. (1980). Significance of circadian rhythms in aerospace operations, (NATO AGARDograph, 247). Neuilly sur Seine, France: NATO AGARD). ↑
  8. See for examples: Gupta, S. & Pati, A. (1994). Desynchronization of circadian rhythms in a group of shift working nurses: Effects of pattern of shift rotation. Journal of Human Ergology, 23(2), 121–131; Tilley, A., Wilkinson, R., Warren, P., Wastson, B., & Drud, M. (1982), The sleep and performance of shiftworkers, Human Factors, 24, 629–641; Tepas, D., Walsh, J., & Armstrong, D. (1981). In L. C. Johnson, D. I. Tepas, W. P. Colquhoun, & M. J. Colligan (Eds.), Biological rhythms, sleep and shift work (pp. 347–356). New York: Spectrum Publishing; Duffy, J., Dijk, D., Klerman, E., Czeisler, C. (1998). Later endogenous circadian temperature nadir relative to an earlier wake time in older people. American Journal of Physiology, 275, R1478–R1487. ↑
  9. See for examples: Lavie, P. (1986). Ultrashort sleep–waking schedule III. ‘Gates’ and ‘forbidden zones’ for sleep. Electroencephalography and Clinical Neurophysiology, 63(5), 414–425; Cabon, P., Bourgeois–Bougrine, S., Mollard, R., Coblentz, A., & Speyer, J. (2000). Fatigue of short–haul flight aircrews in civil aviation: Effects of work schedules. In S. Hornberger, P. Knauth, G. Costa, & S. Folkard (Eds.), Shiftwork in the 21st century: Challenges for research and practice (pp.79–85). Frankfurt: Peter Lang. ↑
  10. Conditions that cause or tend to cause sleep, such as low lighting, few task requirements and/or little to observe outside the aircraft. ↑
  11. TP 14575E, Developing and Implementing a Fatigue Risk Management System, April 2007. ↑
  12. In June 2011, ICAO released DOC 9966 FRMS for Regulators. In July 2011, IATA, ICAO and IFALPA jointly announce the FRMS Implementation Guide for Operators. ↑
  13. CAR 602.02 and Air Canada Flight Operations Manual 2.9.4. ↑
  14. Checklist challenges user to consider pre–duty workload, pre–duty sleep, actual fitness and actual flight duty period. See for example: Valk, P.J.L. and Simmons, M. (1997) Pros and Cons of Strategic Napping in Long Haul Flights, AGARD–CP–599 Aeromedical Support Issues in Contingency Operations, The AMP Symposium, held in Rotterdam, The Netherlands, 29 September – 1 October 1997. ↑
  15. For example: Rosekind, M.R. et al (1994) Crew Factors in Flight Operations IZ: Effects of Planned Cockpit Rest on Crew Performance and Alertness in Long–Haul Operations, NASA Technical Memorandum 108839; Speyer, J.J. et al (2004) Getting to Grips with Fatigue and Alertness Management, Airbus STL 945.2796/04; Simons M, and Valk PJL, (1997) Effects of controlled rest on the flight deck on crew performance and alertness. Netherlands Aerospace Medical Centre Report No. NLRGC 1997–B3. ↑
  16. Controlled Rest – Air Canada FOM, Section 2.9.10 – Alertness Management. ↑
  17. A finding is considered moderate where a surveillance activity has identified that a SMS component and/or element has not been fully maintained and non–conformance findings indicate that the component is not fully effective, but where no immediate safety issues were detected. ↑
  18. Air Canada Flight Operations Manual, 01 Jun 2010, Health and Medical Considerations, Practicing Controlled Rest, p19. ↑
  19. Negative transfer is the detrimental effect of prior experience on the learning of a new task. ↑
  20. Rasmussen J, Pejtersen AM and Goodstein LP (1994) Cognitive systems engineering. Wiley, New York. ↑
  21. Valk, P.J.L. and Simmons, M. (1997) Pros and Cons of Strategic Napping in Long Haul Flights, AGARD–CP–599 Aeromedical Support Issues in Contingency Operations, The AMP Symposium, held in Rotterdam, The Netherlands, 29 September – 1 October 1997. ↑
  22. Lubin, A., Hord, D., Tracy, M., & Johnson, L. (1976). Effects of exercise, bedrest and napping on performance decrement during 40 hours. Psychophysiology, 13, 334–339. ↑
  23. Ferrara, M. & De Gennaro, L. (2000). The sleep inertia phenomenon during the sleep–wake transition: Theoretical operational issues. Aviation, Space and Environmental Medicine, 71, 843–848. ↑
  24. See for examples: Webb, W. & Agnew, H. (1974). The effects of a chronic limitation on sleep length. Psychophysiology, 11, 265–274;Wilkinson, R. & Stretton, M. (1971). Performance after awakening at different times of night. Psychonomic Science, 23, 283–285. ↑
  25. Dinges, D., Orne, M., Whitehouse, W., & Orne, E. (1987). Temporal placement of a nap for alertness: Contributions of circadian phase and prior wakefulness. Sleep, 10, 313–329; Ferrara, M. & De Gennaro, L. (2000). The sleep inertia phenomenon during the sleep–wake transition: Theoretical operational issues. Aviation, Space and Environmental Medicine, 71, 843–848. ↑
  26. For example: Jewitt, M., Wyatt, J., Ritz–De Cecco, A., Khalsa S., Djik D., & Czeisler, C. (1999). Time course of sleep inertia dissipation in human performance and alertness. Journal of Sleep Research, 8, 1–8). ↑
  27. Matchock R. & Mordkoff (2007). Visual attention, reaction time, and self–reported alertness upon awakening from sleep bouts of varying lengths. Experimental Brain Research, 178, 228–239;Dinges, D., Orne, E., Evans, F., & Orne, M. (1981). Performance after naps in sleep–conducive and alerting environments. In L. Johnson, D. Tepas, W. Colquhoun, & M. Colligan, (Eds.), Biological Rhythms, Sleep and Shift Work (pp. 539–553). New York: Spectrum Publications. ↑
  28. See for examples: Dinges, D., Orne, M., & Orne, E. (1985). Assessing performance upon abrupt awakening from naps during quasi–continuous operations. Behavior Research Methods, Instruments, and Computers, 17, 37–45; Lavie, P. & Weler, B. (1989). Timing of naps: effects on post–nap sleepiness levels. Electroencephalography and Clinical Neurophysiology, 72, 218–224;Dinges, D., Orne, M., Whitehouse, W., & Orne, E. (1987). Temporal placement of a nap for alertness: contributions of circadian phase and prior wakefulness. Sleep, 10, 313–329. ↑
  29. See for examples: Dinges, D., Orne, M., & Orne, E. (1985). Assessing performance upon abrupt awakening from naps during quasicontinuous operations. Behavior Research Methods, Instruments, and Computers, 17, 37–45; Ferrara, M., De Gennaro, L., & Bertini, M. (2000). Voluntary oculomotor performance upon awakening after total sleep deprivation. Sleep, 23, 801–811. ↑
  30. See for example: Feltin, M. & Broughton, R. (1968). Differential effects of arousal from slow wave sleep and REM sleep. Psychophysiology, 5, 231. ↑
  31. See for example: Tassi, P & Muzet, A. (2000). Sleep inertia. Sleep Medicine Reviews, 4(4), 341–353. ↑
  32. Matchock R. & Mordkoff (2007). Visual attention, reaction time, and self–reported alertness upon awakening from sleep bouts of varying lengths. Experimental Brain Research, 178, 228–239. ↑
  33. See for examples:Matchock R. & Mordkoff (2007). Visual attention, reaction time, and self–reported alertness upon awakening from sleep bouts of varying lengths. Experimental Brain Research, 178, 228–239; Tassi, P & Muzet, A. (2000). Sleep inertia. Sleep Medicine Reviews, 4(4), 341–353. ↑
  34. Evans, F. & Orne, M. (1976). Recovery from fatigue. Annual Summary Report No. 60. Fort Derrick, MD: US Army Medical Research and Development Command. ↑
  35. Stampi, C., Mullington, J., Rivers, M.,Campos, J., & Broughton, R. (1990). Ultrashort sleep schedules: Sleep architecture and the recuperative value of multiple 80– 50– and 20 –min naps. In J. Horne (Ed.) Sleep ’90 (71–74). Bochum, U.K.: Pontenagel Press. ↑
  36. A circadian high is a period of normal or optimal alertness and performance. Circadian highs occur during the daytime hours for the diurnal person. ↑

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Aviation Reports – 2010 – A10Q0117

| Transportation Safety Board Reports | April 5, 2012

Transportation Safety Board of Canada

Aviation Reports – 2010 – A10Q0117

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Loss of Control and Collision with Terrain
Nordair Québec 2000 Inc.
de Havilland DHC-2 Mk. 1 C-FGYK
La Grande-Rivière Airport, Quebec
24 July 2010

Report Number A10Q0117

Synopsis

At approximately 1053 Eastern Daylight Time, de Havilland DHC–2 Mk. 1 amphibious floatplane (registration C–FGYK, serial number 123), operated by Nordair Québec 2000 Inc., took off from runway 31 at La Grande–Rivière Airport, Quebec, for a visual flight rules flight to l’Eau Claire Lake, Quebec, about 190 nautical miles to the north. The take–off run was longer than usual. The aircraft became airborne but was unable to gain altitude. At the runway end, at approximately 50 feet above ground level, the aircraft pitched up and banked left. It then nosed down and crashed in a small shallow lake. The pilot and 1 front–seat passenger were fatally injured and the 3 rear–seat passengers sustained serious injuries. The aircraft broke up on impact, and the forward part of the cockpit was partly submerged. The emergency locator transmitter activated on impact.

Other Factual Information

During the afternoon of 23 July 2010, the day before the flight, the passengers went to the office of Nordair Québec 2000 Inc. in Radisson, Quebec. The passengers’ baggage was transported in 2 cars. The pilot checked it, and it was agreed that there would be no problem loading it all on the aircraft. The passengers were being flown to l’Eau Claire Lake to join a canoe expedition.

On the day of the accident, the aircraft was fuelled from the facilities at La Grande–Rivière Airport. It was determined that the aircraft took on a total of 374 litres of fuel, including the 3 full belly tanks and 2 more 20–litre containers. Four other 20 L containers were filled with automotive fuel. Two containers were placed in the forward float compartments and the other 4 were placed immediately behind the rear passenger seat in the cabin. Also, a canoe, 18 feet long and 32 inches wide, was tied directly to the right float struts.

The aircraft had 2 forward seats and 1 triple seat aft. The pilot loaded and placed the baggage items behind the triple seat, but did not weigh them beforehand. The pilot let the passengers choose their own seats.

At 1051, 1 the pilot informed the Flight Services Specialist (FSS) that he was ready to taxi for runway 31. In accordance with the Flight Services Manual of Operations (FS MANOPS) procedures, the FSS informed the pilot that runway 13 would be better, due to the wind speed and direction. The pilot acknowledged and advised the FSS that he was taking off from runway 31. He used the full length, which was unusual because he normally took off from the intersection of taxiway Bravo (Appendix A). The aircraft took off at 1053.

The take–off run was longer than usual. Once airborne, the aircraft was unable to gain altitude. The engine noise was constant and it seemed to be operating normally. When the aircraft was approximately 50 feet above ground level (agl) at the runway end, it pitched up and banked left. It then nosed down and crashed in a lake approximately 900 m from the end of runway 31, to the left of the runway centre line. At 1054:30, the emergency locator transmitter (ELT) signal is received.

Although the FSS could not see where the aircraft crashed from his position, he immediately activated the crash alarm. Twenty–three seconds later, he tried calling 911 but a misdial occurred. Afterwards, the FSS was busy communicating by radio with other aircraft and also with the rescue team in charge. As a result, the call to 911 was made about 10 minutes after the crash.

Rescue Information

When the crash alarm was activated, the prevention officer on duty drove the airport fire truck to the runway 13 threshold and saw the aircraft in the lake. However, the truck could not get any closer to the wreckage. An Air Inuit Hawker Siddeley 748 (HS748) flew over the accident site and confirmed that it saw no movement around the aircraft. Two airport employees reached the wreckage by following a trail and wading into the lake. The pilot was still conscious when they arrived at the site. They got one of the rear–seat passengers out and took him to shore. Then, they held the heads of the other 2 rear–seat passengers above water until the rescuers arrived. When the first responders arrived at the airport, they were transported to the accident site by helicopter. A short time later, a second helicopter transported one of the injured to Chisasibi. That evening, the 3 rear–seat passengers were flown to 2 hospitals in the Montreal area.

Information on Airport and Fire Service

La Grande–Rivière Airport is in the Municipality of Radisson. The airport is operated by the Société de Développement de la Baie–James, which holds the Transport Canada (TC) operating certificate.

TC approved the existing emergency measures plan on 17 March 2003. Since 1 January 1997, there was only 1 rescue truck available at the airport. The area under airport responsibility is restricted to airport property only. It covers an imaginary rectangle extending 1000 m beyond each runway end and 150 m either side of the runway centre line. Any response required outside this boundary is the responsibility of the Municipality of Radisson, located 32 km away. The estimated response time for the regular crew is approximately 45 minutes.

Wreckage Information

The aircraft broke into 3 parts on impact. The cockpit part rested on its right side, on the bottom of the lake, in about 1 m of water. The substantial damage to the front of the aircraft showed that it struck the surface of the lake in a vertical attitude, with left bank. The engine compartment was pushed upward and to the right. All float attachment fittings failed due to the force of the impact. Both wings separated forward due to strong forces. The left side of the aircraft was more severely damaged than the right side. The left float sustained substantial compression damage and the nose wheel separated due to the force of the impact.

The cabin floor was not severely damaged. However, the aluminum legs of the triple seat were broken and the seat was completely separated from its attachment fittings, propelling the passengers forward. The seatbelts were anchored directly to the seats. Although baggage tie–down fittings were installed in the aircraft, the baggage was not secured to the floor, and it shifted forward (photo 1).

Photo 1. Baggage shifted toward the front of the aircraft
Photo 1. Baggage shifted toward the front of the aircraft

The 2 front seats were fitted with shoulder harnesses, while the rear triple seat had lap belts anchored directly to the seat. It could not be determined whether or not the pilot and front passenger were wearing their shoulder harness at the time of impact. All 3 rear passengers were wearing their lap belts when the crash occurred.

The damage to the propeller and engine show that the P&W R985–14B engine was developing power at the time of impact. The flap position was measured from the flap actuator cylinder. An impact mark was found on the cylinder ram, indicating that the flaps were lowered at 24.5 °. Normally the flap position on take–off is 35 °.

The landing gear selector mounted on the floor, to the right of the pilot, was in ‘UP’ position, but at the accident site, the wheels were found in the down and locked position. The Flight Supplement states that the normal landing gear retraction cycle takes about 20 to 30 seconds after the selector is placed in the ‘UP’ position.

Weather

At 1000, the weather conditions were as follows: temperature 14.5°C, dew point 13.9°C, winds from the east–northeast, 080° magnetic at 7 knots, broken clouds at 4000 feet agl, overcast at 8000 feet agl, visibility 8 statute miles in rain showers and altimeter setting 29.65 inHg. Due to his increased workload, and higher priorities immediately following the accident, the FSS was unable to make a weather observation at 1100.

Pilot Information

The pilot was certified and qualified for the flight in accordance with existing regulations. He held a valid Canadian commercial pilot – aeroplane licence. In total, he had approximately 3800 flying hours, including about 1000 hours on DHC–2. On 18 July 2009, the pilot had his annual in–flight training on the amphibious DHC–2. Also, this training was to be renewed before 1 August 2010.

The pilot held the following positions in Nordair Québec 2000 Inc.: operations manager, chief pilot, maintenance control system manager and maintenance coordinator.

There was no evidence that incapacitation, physiological or psychological factors affected the pilot’s performance.

Carrier Information

Nordair Québec 2000 Inc. holds a valid operating certificate. The carrier’s base of operations was La Grande–Rivière Airport. At the time of the occurrence, it was operating a fleet of 3 aircraft: a DHC–2 Beaver, a DHC–3T Turbo Otter and a Piper Navajo PA–31. The aircraft were operated under Part VII, Subparts 2 and 3 of the Canadian Aviation Regulations (CARs). At the time of this occurrence, the aircraft was being operated under Subpart 3. 2

Aircraft Information

The DHC–2 Mk. 1 is a single–engine piston aircraft used widely in bush flying operations. It can be used on wheels, skis or floats or in amphibious configuration (wheels/floats). The C–FGYK was purchased by the carrier in February 2009. It was built in 1951, and the log book indicated that as of 22 July 2010, it had accumulated 23 886.9 airframe hours since new. The last 100–hour inspection was completed on 5 July 2010, when the aircraft had 23 808.3 hours. After that date, there were no deficiencies reported in the log book.

The aircraft was not equipped with on–board recorders, nor were they required by regulation. Without recorders, it was difficult to establish the sequence of events that led to the accident.

Weight and Balance Report

On 29 May 2009, Wipline model 6000A amphibious floats were installed. Also, airframe modifications 3 were made to increase the maximum allowable take–off weight to 5600 pounds. A new weight and balance report was done, resulting in a dry weight of 3778.10 pounds. According to the Aircraft Flight Manual Supplement 4 issued with this modification, the centre of gravity (CG) should be between −2.6 inches and −6.11 inches from datum. 5

The carrier’s weight and balance report form was not amended after the new amphibious floats were installed, and it contained an error in the forward CG limit, which was −1.25 inches for amphibious float configuration. 6 The aft CG was the same in both float configurations, i.e., −6.11 inches.

Subsection 703.37(1) of the CARs states that no person shall operate an aircraft unless, during every phase of the flight, the load restrictions, weight and CG of the aircraft conform to the limitations specified in the aircraft flight manual. Nordair Québec 2000 Inc. used an approved pilot self–dispatch system. Under this system, pilots are required to do weight and balance calculations before every flight. Where possible, the pilot should leave a copy of the weight and balance report at the point of departure. No report was found for this flight.

The carrier operations manual 7 states that the aircraft take–off weight must be reduced to 5300 pounds when carrying a canoe as external cargo, and that the total take–off weight of the aircraft must be reduced by twice the total weight of that external payload. Since the canoe being transported weighed 70 pounds, the maximum allowable take–off weight of 5300 pounds should have been reduced by 140 pounds. Consequently, the maximum allowable take–off weight for this particular flight was 5160 pounds.

To determine as accurately as possible the weight of the aircraft on take–off, the baggage was recovered on the evening of the accident and left under supervision in a dry place. The baggage was weighed during the afternoon of the following day. Together, the baggage and the 6 containers of fuel weighed approximately 900 pounds. The weight of the canoe, 70 pounds, must be added to that figure.

Based on the actual weight of the passengers, and considering the quantity of fuel, the baggage and the canoe on departure, the overall weight of the aircraft was determined to be 6162 pounds, which means it was 1002 pounds overweight. As for the CG, it was at 111.80 inches, or 5.69 inches beyond the CG aft limit (Appendix B).

Information on Triple Seat

The rear triple seat was secured to the floor structure by 6 attachment fittings, 4 at the front and 2 at the rear. Three of the 4 fittings at the front failed, while the 2 rear fittings did not fail but separated from their floor–mounted receptacles. On impact, most of the inertial forces acted in the forward direction and laterally due to the left angle of impact. The rear leg fittings for the triple seat were subjected to tension forces, while the front leg fittings were subjected to compression forces. When the accident occurred, the seat pivoted forward, causing the front fittings to fail in tension. The occupants were propelled forward.

Comparison of the construction of the triple seat with the original drawings, obtained by the owner of the type certificate, 8  revealed that it met the construction standards, except for the welds and the addition of sheet metal to the rear of the seat back. These deviations from the original drawings did not contribute to the separation of the seat from the floor. The types of materials used, as well as the dimension and thickness of the tube stock, the attachment fittings and the nuts and washers were essentially consistent with the original drawings. Since the seat had no nameplate, it is possible that it was not an original de Havilland seat or that it had undergone substantial repairs over the years.

On original certification of the triple seat, it was designed to hold 3 occupants each weighing 170 pounds, for a total of 510 pounds. When the impact occurred, the 828 pounds of items, not tied down to the floor, shifted forward and pushed against the seat. As a result, the seat would have had to withstand the weight of the passengers in addition to 828 pounds of baggage, for a total of 1435 pounds. The forward shifting of the unsecured baggage considerably diminished the capacity of the seat to remain anchored.

Take–off Performance

The take–off performance of the aircraft was calculated in the conditions that existed at the time of this take–off based on the following elements:

  • wind 080° at 7 knots, 9 resulting in a tail wind component
  • certified maximum take–off weight of 5600 pounds in accordance with STC no SA01324CH
  • temperature during take–off at 15°C
  • elevation of La Grande–Rivière Airport of 640 asl.

The calculations indicate a take–off distance of 1263 feet plus tail wind take–off distance of 918 feet, for a total of 2181 feet, to clear a 50–foot obstruction. Instead of calculating the total weight of the aircraft at the time of the accident, the figures used in the performance calculations were the maximum weight allowable according to Wipaire STC SA01324CH, which is 5600 pounds.

DHC–2 Stall Characteristics

The DHC–2 was built and certificated according to British Civil Airworthiness Requirements (BCAR), as amended on 1 June 1947. When the DHC–2 was certificated in 1948, certification requirements were less stringent than they are today. More recent single–engine aircraft are certificated according to CARs, Part V, Standard 523 or equivalent. CARs require that aircraft be equipped with a stall–warning device to give the pilot a clear and distinctive warning of the impending stall. The DHC–2 is not equipped with a visual or audible stall–warning device, nor was it required for certification at the time.

The DHC–2 flight manual provisions 10 relating to flight characteristics, and specifically to stall characteristics, state that the aircraft is easy to fly and controllable all the way to the stall. Stalling is gentle in all normal conditions of load and flap configuration, and it is preceded by a slight vibration that increases when the flaps are extended. Aircraft pitch changes if there is no yaw. If the yaw is not controlled, the aircraft tends to roll. Corrective action must be taken quickly to prevent the roll from developing.

Aeronautical Testing Service Inc. (ATS), in Washington, U.S.A., is an aviation consulting and manufacturing firm mainly involved in designing, developing and manufacturing modifications for general aviation aircraft. ATS did flight tests with an unmodified DHC‑2 Mk. 1 as part of the design process for a vortex generator for this aircraft type. The aim of the tests was to evaluate the stall characteristics, stall warnings and stall control in accordance with the BCAR.

The flight test report indicates that the test aircraft’s stall characteristics were acceptable with a forward CG. However, with an aft CG and power, incipient stalls with 60° of roll, 30° to 40° of yaw, and 30° of pitch occurred often on these flight tests. The ATS flight test report indicates that, with flaps set for the climb, take–off or landing, the ailerons and rudder were effective until the aircraft stalled but were not effective in controlling abrupt roll or yaw after the stall occurred.

Carrying External Loads

Carriage of external cargo by a commercial carrier in Canada must be evaluated and approved by Transport Canada (TC). On 9 June 2009, to allow the in–flight assessment to be done, TC issued a permit for experiment flights over a period of 30 days. Flight Test Plan 093023 from JCM Aerodesign Ltd. was used. One of the restrictions stipulated in the experiment flight permit was that the canoe could not exceed 150 pounds in weight, 14 feet in length and 42 inches in width.

Further, in accordance with TC‘s Advisory Circular 500–004, 11 the maximum allowable take–off weight should be reduced to 5300 pounds when a canoe is carried or to 5000 pounds when 2 canoes are carried.

Section 703.25 of the CARs provides as follows: “except where carriage of an external load has been authorized in a type certificate or supplemental type certificate (STC), no air operator shall operate an aircraft to carry an external load with passengers on board.” The Minister issued an exemption to CARs 703.25, which was to be in effect until 31 December 2010 at 2359 hours.

To be eligible for this exemption, the air operator must first register their intended use of the exemption, prior to engaging in the carriage of external loads under the authority of this exemption, by providing specified information. Even though the carrier had conducted the flight tests, it had not submitted any documents for approval.

Consequently, it was not authorized to carry external loads. However, the operations manual 12 states that DHC–2 aircraft C–FGYK is approved under a limited STC to carry canoes as external cargo. This amendment was approved by TC on 1 March 2010, despite the fact that no STC had been issued for this aircraft.

Transport Canada Regulatory Oversight

TC‘s Commercial and Business Aviation (CBA) Division is responsible for the oversight of commercial air operations that fall under CARs 700. The CBA has an Air Operator Certification Standards Unit (AOCSU) responsible for handling applications for new operations and for changes to existing operations. It also ensures that air operators meet the required standards according to the Commercial Air Service Standards Unit (CASSU).

The AOCSU monitors day–to–day operations to ensure that the company is conducting business in accordance with its Air Operator Certificate (AOC). It also exchanges information on related issues, as required. Also, the AOCSU ensures that commercial air operators comply with the Commercial Air Service Standards (CASS).

Also, the CASSU ensures compliance oversight through formal audits, inspections and pilot proficiency checks. Each air operator has an assigned principal operations inspector (POI) who monitors the company’s operations. The activities of the POI are governed by the Air Carrier Inspector Manual (ACIM), TP 3783.

In 2003, TC‘s CASSU assigned Nordair Québec 2000 Inc. a POI who carried out the regulatory oversight of the company through e–mails, telephone conversations, and routine visits to the air operator’s La Grande–Rivière and Radisson facilities.

One of the various types of audits performed by TC is the program validation inspection (PVI), which is a process comprising a targeted inspection of one or more aspects of an organization that is, or is not, required to have a safety management system (SMS) and another one that targets inspections of an organization that is in the process of introducing an SMS.

Program validation inspections are carried out at regular intervals and take into account risk indicators to adjust the frequency, if necessary. The PVI may include an examination of one item in particular or an evaluation of one person according to established standards. A TC inspection can result in major consequences, including the cancellation of an air operator certificate.

Following a PVI, a score from 1 to 5 is assigned. Two PVIs took place: a maintenance PVI in 2009 and an operation PVI in 2010. During the maintenance PVI in 2009, the air operator was given a score of 2 because its quality assurance system was deemed ineffective.

It was up to the convening authority to decide what type of monitoring to apply. Subsequently, the decision–maker selected enhanced monitoring.

When a score lower than 3 is assigned, or if there are major findings of non–conformance, TC manages the risk associated with the findings by asking the certificate holder to submit a detailed corrective action plan that addresses these findings.

Since 2003, Nordair Québec 2000 Inc. has been audited several times by TC, which conducted

  • 2 regulatory audits of operations;
  • 2 regulatory audits of maintenance;
  • 4 operations ramp inspections;
  • 3 maintenance ramp inspections;
  • 1 maintenance PVI; and
  • 1 operations PVI.

Conducted over a period of 7 years, these audits revealed the following: 20 cases of operations non–conformance, 16 cases of maintenance non–conformance, and 38 cases of non–conformance with respect to aircraft condition. It should be noted that the 38 cases of non–conformance observed by TC inspectors included

  • personnel training;
  • flying with uncorrected mechanical deficiencies;
  • absence of baggage tie–down devices (4 times);
  • non–compliance related to log–book entries;
  • aircraft maintenance status;
  • non–compliance with Maintenance Control Manual procedures; and
  • ineffective quality assurance system.

Each time, a corrective action plan was submitted to TC, and each time the plans were approved. Nevertheless, subsequent inspections revealed that similar anomalies were recurring.

Aviation Enforcement Philosophy

TC‘s aviation enforcement policy recognizes that “voluntary compliance” with the regulations is the most progressive and effective approach in achieving aviation safety. It is assumed that members of the aviation community share an interest, commitment and responsibility with regard to aviation safety, and that they will perform their activities showing common sense, responsibility and respect for others.

However, TC believes that there are individuals in the aviation community who are less motivated by common sense, personal and civil responsibility, pride and professionalism, and especially safety. It is these individuals who are the focus of enforcement action.

TC is committed to enforcing the regulations fairly and firmly, while encouraging communication between the alleged offenders. Also, TC offers “oral counselling” for minor violations where there is no threat to aviation safety, and it also informs offenders of their right to have penalties reviewed by the Transportation Appeal Tribunal of Canada (TATC). TC also ensures that strict measures are taken against repeat offenders and those displaying flagrant disregard for aviation safety.

Since 2003, the Enforcement Section has received 3 Detection Notices concerning Nordair Québec 2000 Inc., all of which have resulted in financial penalties.

The following laboratory reports were completed:

LP127/2010 – Flight instruments analysis
LP128/2010 – Flap actuator analysis
LP177/2010 – Triple seat analysis
LP178/2010 – Propeller analysis.

These reports are available from the Transportation Safety Board of Canada upon request.

Analysis

Although the winds favoured runway 13, the pilot elected to take off from runway 31. While a tail wind component increased the take–off distance, the runway length available was sufficient for a take–off at the maximum allowable weight, even from intersection Bravo. It was unusual for C–FGYK to use the full length of runway 31 for a take–off. It is likely that the pilot allowed for the effect of the tail wind component on the take–off distance, and that he knew he was overweight. Not having weighed the baggage, the pilot could not know the precise weight and balance status of the aircraft on take–off.

It is not known why the pilot did not weigh or secure the baggage. Weight and balance calculations confirm that the aircraft was overweight on take–off and that its centre of gravity (CG) was aft of the limit prescribed in the STC on the installation of new amphibious floats. In such a case, the stall speed was higher and the stall characteristics caused changes of altitude which are hard to counteract, making recovery difficult.

Further, the aft CG reduced the distance between the CG and the centre of pressure of the vertical stabilizer, thereby decreasing the effectiveness of the rudder and making recovery more difficult. Although a stall warning device would have alerted the pilot to the impending stall, with the CG beyond the aft limit, the aircraft pitched up quickly. When the aircraft was out of the ground effect, it stalled at an altitude that did not allow the pilot to execute the recovery manoeuvre.

Although the carrier did flight tests in order to apply for authorization to carry external loads, it did not file the required documents for approval. Thus, the carrier did not have approval to carry a canoe, although the section of its operations manual relating to external loads was approved by TC. Moreover, as stated in the flight test documents, the dimensions of the canoe exceeded the limits specified in the approval document. The aerodynamic effects of carrying a canoe longer than the limit allowed by the experiment flight permit are unknown. Operating an aircraft outside the limits and conditions under which a permit is issued can increase the risk of an accident.

The construction and installation of the triple seat was, with few exceptions, consistent with the manufacturer’s original drawings and allowed it to withstand some impact forces. However, the forward shift of the unsecured baggage was a major contributing factor in the injuries sustained by the 3 rear–seat passengers, who were propelled towards the cockpit when their seat pivoted forward.

Since 2003, TC has performed inspections and audits of the company’s facilities and the results indicated several findings of non–conformance. Although in each of these cases, a corrective action plan was submitted to and approved by TC. However, the same anomalies were again observed in subsequent inspections, in spite of previous monetary penalties. For example, TC inspectors have noted on 4 occasions that the baggage tie–down system was not installed or not used, as was the case in this accident.

Given Nordair Québec 2000 Inc.‘s latest evaluation score and the 3 previous Detection Notices, it is obvious that enhanced monitoring would have resulted in an in–depth analysis of their management, in addition to targeting repeated deficiencies. The action taken by TC did not have the desired outcomes to ensure regulatory compliance; consequently, unsafe practices persisted.

Although the flight services specialist activated the crash alarm upon receiving the ELT signal, and the prevention officer on duty immediately headed for the site, the officer could not get close to the wreckage. Because  the aircraft crashed outside the airport property limits, the Municipality of Radisson was responsible for responding. Given that the regular rescue crew’s response time was about 45 minutes, and that the 911 call was made about 10 minutes after the crash, it is estimated that it took at least 55 minutes for the first responders to arrive. Like the airport prevention officer, the first responders were unable to get close to the wreckage with their vehicle. It was necessary to use a helicopter. The assistance provided to the 3 rear–seat passengers by the 2 persons who went to the site before the arrival of the first responders probably saved them from drowning.

Findings as to Causes and Contributing Factors

  1. The aircraft was overloaded and its centre of gravity was beyond the aft limit. The aircraft pitched up and stalled at an altitude that did not allow the pilot to execute the stall recovery manoeuvre.
  2. The baggage was not secured. Shifting of the baggage caused the triple seat to pivot forward, propelling the 3 rear–seat passengers against the pilot and front–seat passenger during impact.
  3. Although the design of the triple seat met aviation standards, it separated from the floor at the time of impact, principally due to the fact that the heavy cargo shifted.
  4. The action taken by TC did not have the desired outcomes to ensure regulatory compliance; consequently, unsafe practices persisted.

Finding as to risk

  1. Operating an aircraft outside the limits and conditions under which a permit is issued can increase the risk of an accident.

Other Finding

  1. The carrier’s operations manual had been approved by Transport Canada for the carriage of external loads despite, despite the fact that the carrier did not have the required supplemental type certificate (STC).

Safety Action Taken

NAV Canada

Following the accident, unit staff received updated procedures and checklists to follow in the event of a crash. Emphasis was placed on calling 911 as soon as possible, as well as performing meteorological observations after an accident. In addition, the button assigned to 911 on all unit telephones was coloured red to facilitate and expedite calling 911.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 29 February 2012.

Appendix A – Aerodrome Chart

Appendix A - Aerodrome Chart

Appendix B – Weight and CG Calculations

Description Weight
(in pounds)
Centre
of Gravity
Moment
Last weight and balance report (amphibious) 3,778 101 381,578
Pilot 170 93 15,810
Front passenger 140 93 13,020
First rear passenger 180 129 23,220
Second rear passenger 180 129 23,220
Third rear passenger 175 129 22,575
Rear baggage including 4 containers of fuel (cabin) 828 162 134,136
2 containers of fuel in float compartments 72 32 2,304
Canoe 70 100 7,000
Fuel in forward tank 209 95.5 19,959.5
Centre fuel tank 209 119.6 24,996.4
Fuel in aft tankFuel in aft tank 151 140 21,140
Total Weight 6,162 111.80 688,958.9
Maximum allowable weight with canoe IAW AC 500–0044 5,160
Aft centre of gravity limit (−6.11) 106.11
Overload and distance from aft centre of gravity 1,002 5.69

  1. All times are Eastern Daylight Time (Coordinated Universal Time minus 4 hours). ↑
  2. Air taxi operation. ↑
  3. Wipaire Supplemental Type Certificate SA01324CH. ↑
  4. Aircraft Flight Manual Supplement dated 29 September 2009, section 2, G. ↑
  5. According to Note 10 of the fact sheet of type certificate A–22, the value 100 is now used as datum. Based on this new value, the CG should be between 102.6 and 106.11. ↑
  6. Amphibious float model Bristol 348–4580. ↑
  7. Subsection 3.27.6(c). ↑
  8. Viking Air Limited. ↑
  9. Calculation based on a tail wind component of 10 knots. ↑
  10. Section 4, subsection 4.11.5. ↑
  11. Transport Canada. “Assessing the Effect of Carrying External Loads on Aircraft”. Advisory Circular 500–004. ↑
  12. Part 3, Carrying external loads – Seaplanes, section 3.27, subsection 3.27.5(a). ↑

 

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Aviation Reports – 2010 – A10O0240

| Transportation Safety Board Reports | March 16, 2012

Transportation Safety Board of Canada

Aviation Reports – 2010 - A10O0240

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Loss of Control and Collision with Terrain
Seneca College of Applied Arts and Technology
Bonanza F33A C–GSCZ
Toronto/Buttonville Municipal Airport, Ontario
10 nm E
18 November 2010

Report Number A10O0240

Synopsis

At approximately 1819 Eastern Standard Time, the Seneca College of Applied Arts and Technology (hereafter Seneca College) Beechcraft F33A aircraft (registration C–GSCZ, serial number CE–1709) departed Toronto/Buttonville Municipal Airport for Kingston Airport, Ontario, on a night visual flight rules flight with an instructor and two commercially–qualified students on board. Weather en route began to deteriorate and the aircraft was headed back to Toronto/Buttonville Municipal Airport. The aircraft was observed on radar to be westbound in level flight before it turned north and began to climb. The aircraft then turned abruptly to the left and descended; radar contact was lost. The aircraft was subsequently located in a ploughed level field approximately 10 nautical miles east of the Toronto/Buttonville Municipal Airport. It was destroyed on ground impact and the three occupants were fatally injured. There was no fire and the emergency locator transmitter did not activate. The accident occurred at approximately 1844 Eastern Standard Time during the hours of darkness.

Other Factual Information

History of Flight

The purpose of the flight was to fly at night under visual flight rules (VFR) to the Kingston Airport (CYGK) to practise instrument flight rules (IFR) approaches before returning to Toronto/Buttonville Municipal Airport (CYKZ) later in the evening. It was planned that one student would fly from the left seat to CYGK while the other was seated in the back. They would switch at CYGK and the second student would fly simulated instrument approaches. The students would switch seats again for the return flight. The instructor was the pilot–in–command and was seated in the right seat. The aircraft departed CYKZ at approximately 1819 1 with the first student in the left seat as planned.

Approximately 11 nautical miles (nm) east of the Oshawa Airport (CYOO), the flight crew reported deteriorating weather conditions and decided to return and perform a simulated RNAV approach at CYKZ.

During the return flight, radar information indicated that C–GSCZ maintained an altitude of approximately 2300 2 feet above sea level (asl) and a ground speed of 130 knots (approximately 115 indicated air speed (IAS)) 3 on a track of 260 degrees 4 true. As it proceeded, C–GSCZ contacted CYKZ tower and requested clearance to perform a simulated area navigation (RNAV) approach to Runway 33. The instructor handled Radio communication with CYKZ, suggesting that the student was flying the aircraft. The CYKZ tower controller provided the clearance for the approach with instructions to maintain VFR, not to exceed 2500 feet asl and report when passing LOBNI (see Appendix A). Instead of reading back the clearance or otherwise acknowledging the clearance as would have been the norm, the instructor’s response was “standby”. There were no further radio transmissions from the aircraft.

Immediately after this last communication, the radar indicated the aircraft began a climbing right turn to a track of 330°. The airspeed reduced to approximately 90 knots IAS during the climb. The second last radar contact showed the aircraft climbing through an altitude of 2800 feet asl, and turning westbound to a track of 277° with a further reduction to 50 knots IAS. The last radar contact at about 1843 indicated the aircraft was tracking 211°, descending rapidly through 2100 feet asl with the IAS at 90 knots and increasing (see Figure 1).

A second Seneca College Bonanza aircraft that was training in the CYOO Airport area was requested by the tower to break off training and head westbound to the area of the last radar contact with C–GSCZ but was unable to locate the aircraft. A police helicopter was also dispatched to the same area and, using a search light, was able to locate the wreckage.

Figure 1. Actual flight path
Figure 1. Actual flight path

Wreckage Description and Examination

The wreckage was located in a level ploughed field in a non–residential area at an elevation of 695 feet asl. The aircraft struck the ground right side up, nose down at an angle of 40° creating a shallow crater. The wings also struck the ground and left ground scars which indicate that the aircraft was in a near wings–level attitude.

The aircraft broke up on a track of 303° and came to rest 350 feet from the original point of impact. The wreckage trail comprised several airframe components including the propeller, doors, panels and seats. The engine remained partially attached to the main wreckage. The left horizontal stabilizer separated from the empennage and was located along the wreckage trail.

The vertical and right horizontal stabilizer remained attached to the separated aft fuselage section. The wings partially separated but remained in proximity of the main wreckage. The aircraft’s cabin was substantially damaged with no remaining structural integrity. The left and right wing attachment fittings remained attached to the carry–through structure. On impact, the wings failed in overload outboard of the attachment fittings. Continuity check of all primary flight controls cables was confirmed. The flaps and the landing gear were fully retracted. The integrity of the seats and restraining systems were compromised during the impact sequence. Overall examination of the wreckage determined that the aircraft was intact prior to impact.

Due to the extent of damage to the wings, it could not be determined if the stall vane was serviceable prior to impact.

Examination of the two control columns identified their position on the aircraft. Both columns were found along the wreckage trail. The left presented little damage in comparison to the right. The right had both handles sheared at the base in overload.

The engine was later disassembled and examined. There was no evidence of any pre–impact internal engine failures. The damage to the variable pitch propeller was indicative of the engine producing power prior to the ground impact. There was no engine instrument evidence to indicate the amount of engine power being produced at the time of impact.

The ELT was damaged during the impact and was found separated from the aircraft in the field. The antenna cable was detached from the ELT and therefore it was unable to transmit a signal.

Aircraft

This F–33A Bonanza was a four–place low–wing monoplane equipped with retractable landing gear, a 285–horsepower Teledyne Continental Motors IO–520 engine, and a 3–blade Hartzell propeller.

Records indicate that the aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The aircraft was manufactured in November of 1992 and was registered in Canada to Seneca College since December of 1992. It was certified to be operated by a single pilot and was considered by Seneca College to be appropriate for its flight training operations. Seneca College operated 5 Beechcraft Bonanza F33As at the time of the occurrence.

The aircraft was maintained under an approved Continuous Care Inspection maintenance program. It had accumulated approximately 10 116 hours of flight time. Its last inspection was performed 8 days prior to the occurrence and had since accumulated 16 hours. Maintenance records indicate that there were no deferred defects, except for the electric pitch trim which had been de–activated earlier in the year. Manual pitch trim was used to operate the pitch trim system.

The aircraft was equipped with dual flight controls allowing for control from either of the two front seats. The instrument panel was arranged where all flight instruments were on the left side in front of the student, engine instruments in the center, and radios and navigation equipment, including the GPS, on the right, in front of the instructor.

The aircraft was not certified or equipped to fly in icing conditions, and only the pitot probe located under the left wing’s leading edge was electrically heated. The stall warning vane, also located on the left wing leading edge, was not heated.

The aircraft was limited to a never exceed indicated airspeed of 196 knots, and at the maximum gross weight of 3400 lbs, the aircraft stalls at an indicated airspeed of 63 knots with flaps retracted and 51 knots with flaps extended. The pilot operating handbook does include an emergency speed reduction procedure of dropping the landing gear to prevent excessive speed build up in case of pilot disorientation or loss of control.

Electric Pitch Trim System

C–GSCZ was involved in an occurrence on 21 June 2009 when 2 students had difficulty controlling the electric pitch trim system during an approach with the landing gear and flaps extended. The trim motor began to operate without being selected by the students resulting in the aircraft pitching nose up abruptly. It required the effort of both students to maintain level flight. The electric pitch trim system eventually disconnected by itself and the aircraft landed safely. The electric pitch trim system master switch had not been selected off during the event. Maintenance personnel were unable to duplicate the fault, but as a precaution, Seneca College de–activated the electric pitch trim systems on all of its Bonanza aircraft.

The Transportation Safety Board (TSB) became involved in this previous occurrence. The electric pitch trim motor assembly was retrieved and shipped to the TSB Laboratory (Occurrence A09O0133). During examination, the only fault found was that one of the magnetic shields for the clutch solenoid had failed in fatigue. It was not determined whether the shield failure contributed to the trim runaway condition. The only other manner that the clutch would have remained engaged was if a short existed in the control switch or the wiring from the switch to the servo. However, maintenance conducted several tests and was unable to duplicate the fault. According to maintenance records, the electric pitch trim system remained de–activated on this aircraft.

Because of this previous occurrence, the TSB examined the remaining components of the trim system. The system circuit breaker located on the right instrument sub panel was substantially damaged and its position could not be determined. However, tests on the other trim system components and the aircraft wiring did not reveal any anomalies that would suggest the electric trim system was either powered or operating at the time of the accident.

Instructor Flying Experience

The instructor was certified and qualified for the flight in accordance with existing regulations. He held a commercial pilot licence with a group 1 instrument rating and was qualified to fly single and multi–engine land aircraft. The instructor was a graduate of the Seneca College flying program who was subsequently hired by Seneca College as an instructor in July 2008. Since that time he had accumulated approximately 900 hours as an instructor. One month prior to the occurrence he was issued a Class 1 Flight Instructor rating.

A review of his flying record dating back to April 2009 indicated that he had flown 23.7 hours in night conditions. Since that date his total instrument instruction time was 13.7 hours of which 2.7 were flown in night conditions. All of the instrument hours were flown two months prior to the occurrence. He had a total of 234.1 hours on the Bonanza F33A, of which 41.2 were instrument and 3.1 at night.

Table 1 shows other total flying times in hours based on the instructor’s log book:

Table 1. Total flying times in hours based on the instructor’s log book
Total Flying Time PIC
Single Engine Aircraft
PIC
Multi Engine Aircraft
PIC
Night Flying
Single Engine
Instrument Actual Instrument Total
1254.3 1098.5 2.5 63.6 7 175 5

Student Flying Experience

The student flying held a valid commercial pilot licence. The following chart indicates the student’s flying experience in hours including total time flying prior to entering the Seneca College flight program:

Table 2. Student’s flight hours prior to entering the Seneca College flight program
Total Flying Time PIC
Single Engine Aircraft
Night Flying On Bonanza F33A PIC On Bonanza F33A Daytime Dual Daytime Flying on Bonanza F33A Instrument Total
207.4 90.4 4 32 23 47

Intended Flight Path

The aircraft was expected to remain in VFR conditions, climb 200 ft and maintain an altitude of 2500 feet asl while turning south to intercept the RNAV Runway 33 approach procedure. Upon reaching VIGSA the aircraft would turn northbound to a track of 333° magnetic. Once past this waypoint, the aircraft would have begun to descend to 1500 feet asl and, upon overflying waypoint LOBNI, would have contacted Buttonville tower. This is a standard published procedure for an RNAV (GNSS6 approach to Runway 33, which the aircraft was intending to perform.

Radar data indicates that after receiving the clearance from the tower, the aircraft was in a climbing right turn toward the north. As the aircraft climbed from approximately 2300 up to 2800 feet asl the IAS dropped from 115 knots to 60 knots. The aircraft then started rolling to the left but the airspeed dropped further to 50 knots. This was followed by a rapid loss of altitude and a correspondingly rapid increase in airspeed. The last radar contact showed the aircraft at an altitude of approximately 2100 feet asl descending rapidly at 9600 feet per minute and accelerating through 140 knots.

Assuming a constant rate of descent at approximately 9600 feet per minute, the time required to reach ground elevation would have been 8.6 seconds.

Turning Stall

When an aircraft is in a climbing turn, the higher wing is at a greater angle of attack than the lower wing. If the aircraft approaches the stall airspeed, the higher wing will stall first turning the aircraft in the direction of the higher wing. Engine power results in an increased airflow over the inboard sections of the wing during the approach to stall. This causes a delayed separation of the airflow compared to the outboard sections where the ailerons are located. The outboard section stalls before the inboard and if an asymmetry exists between the wings, the wing drop will be more pronounced. The flight manoeuvre that was observed on radar and further supported by engineering estimations was indicative of a wing stall.

Meteorological Conditions

CYKZ, located approximately 10.5 nautical miles (nm) west of the occurrence site, at 1900 on the evening of the occurrence, was reporting the winds from 280° at 6 knots and the visibility at 15 miles, a few clouds at 2000 and 5000 feet, a temperature of 2.3° and a dew point of −0.6°C. At 2000, the winds were from 300° at 4 knots, visibility 15 miles, a few clouds at 2000 and 22 000 feet, a temperature of 1.4°C and a dew point of −0.8°C.

The CYKZ forecast for the time period was for winds from 300° at 5 knots, visibility more than 6 miles, a few clouds at 3000 feet and broken clouds at 6000 feet. Temporarily reduced visibility to 5 miles in light rain showers and mist, with broken clouds at 2000 feet and winds from 330° at 10 gusting 20 knots was forecast to be over approximately 2 hours prior to the occurrence. The later part of the forecast period indicated winds from 320° at 5 knots, visibility more than 6 miles and a few clouds at 3000 feet.

CYOO, located approximately 10.4 nm east of the occurrence site, at 1900 on the evening of the occurrence, was reporting the winds from 310° at 5 knots and the visibility at 9 miles, scattered clouds at 3600 feet and broken clouds at 4500 feet, a temperature of 1°C and a dewpoint of 1°C.

There were 4 special weather observations for CYOO as follows:

  • At 1919, the winds were from 340° at 6 knots, variable from 290° to 350°, visibility still at 9 miles, scattered clouds at 1500 feet, broken clouds at 2400 and 3600 feet with the temperature and dewpoint still at 1°C.
  • At 1923, the winds were from 320° at 5 knots, visibility at 9 miles, scattered clouds at 1500 and 2000 feet, broken clouds at 2600 and 3400 feet, a temperature of 2°C and dewpoint of 2°C.
  • At 1932, the winds were from 320° at 5 knots, visibility at 9 miles, scattered clouds at 1700 feet, broken clouds at 2200, 2900 and 3900 feet, a temperature of 2°C and dewpoint of 2°C.
  • At 1933, the winds were from 310° at 6 knots, visibility at 9 miles in light rain, scattered clouds at 1700 feet, broken clouds at 2200 and 2700 feet, overcast clouds at 3700 feet, a temperature of 2°C and dewpoint of 2°C.

The next regular weather observation for CYOO, at 2000, was reporting the winds from 350° at 5 knots, visibility at 9 miles in light rain, overcast clouds at 1400 feet, a temperature of 2°C and dewpoint of 2°C.

There was no Terminal Area Forecast for CYOO.

Figure 2. Location of Accident Site and Weather Conditions
Figure 2. Location of Accident Site and Weather Conditions

Environment Canada radar indicated precipitation in the form of rain moving in a southerly direction towards Lake Ontario from Lake Huron. The graphical area forecast (GFA) clouds and weather forecast for Ontario region valid at 1900 hours, forecasted isolated towering cumulus clouds, 2 statute miles visibility in light snow showers with a ceiling of 1000 feet agl over and off Lake Huron. The GFA icing turbulence and freezing forecast issued at 1242 and valid at 1900 showed no icing being forecast with a freezing level at 2500 feet asl. A second GFA issued at 1832 and valid at 1900 showed moderate mixed icing between 3000 to 9000 feet asl. This forecast was not available prior to the aircraft departing CYKZ. Although no PIREPS were received prior to the occurrence, aircraft in the vicinity and at an altitude of 2500 agl, were encountering light icing conditions with mixed precipitation, and a temperature of approximately − 2°C.

Although CYKZ and CYOO airports were reporting VFR weather conditions, at the mid–point between the two, there were ground reports of rain mixed with snow with temperatures suitable to icing.

The following TSB Laboratory reports were completed:

LP162/2010 – Instrument Analysis
LP164/2010 – Radar and ATC Synchronization
LP191/2010 – Aircraft Performance Analysis

Analysis

The analysis will focus on the environmental conditions at the location of the occurrence, and provide a plausible scenario for the deviation in the flight path that led to the loss of directional control and rapid descent with no recovery prior to ground impact.

Deteriorating weather conditions encountered enroute prompted the flight crew to cancel the planned flight to CYGK and return to CYKZ. Radar data and recorded voice communications indicate that the return flight was normal until the climbing right turn. During that turn, airspeed was allowed to decrease suggesting that engine power was not increased to maintain a safe airspeed. The aircraft rolled into a steep left turn with a high rate of descent. The flight manoeuvre that was observed on radar and further supported by engineering estimations indicates a left wing stall followed by an abrupt left wing drop. The abruptness of the wing stall could have been exacerbated by any airframe icing which may have accumulated on the wings.

Weather information from other aircraft in the vicinity and from ground observations indicated that local weather conditions which included rain, snow, and freezing rain, were quite different to the conditions at either CYOO or CYKZ. Encountering these weather conditions unexpectedly may have influenced the crew’s decision to intentionally deviate to the north to find better weather. Outside visual reference may have also been hampered by these weather conditions and by darkness.

Although it is impossible to ascertain who was controlling the aircraft at the time, it is logical to assume that the student was at the controls while the instructor was requesting the approach clearance. When the aircraft stalled, the instructor would have been attempting to recover control. The rapidity of the stall, the airspeed during the descent and the lack of available altitude prevented a full recovery before the aircraft struck the ground. This would have been compounded by limited visual reference due to the weather conditions and the lack of flight instruments on the right side of the instrument panel.

There were approximately 8 seconds between the loss of control and when the aircraft struck the ground assuming a constant rate of descent of 9600 feet per minute. Ground impact marks show that, although the aircraft was nose down, it was in a near wings level attitude, suggesting that the recovery had been initiated but altitude and excessive descent speed precluded full recovery.

Findings as to Causes and Contributing Factors

  1. After encountering adverse weather conditions, a climbing right turn was initiated. During the climbing turn, engine power was likely not increased and the airspeed decayed. The angle of attack on the left wing was allowed to increase until it stalled and dropped unexpectedly.
  2. The location of the flight instruments made it more difficult for the instructor in the right seat to see and react to them and control of the aircraft was not regained before the aircraft struck the ground in a non–survivable impact.

Safety action

Seneca College has instituted the following changes to its training program to enhance flight safety:

  • Group weather briefing – This is attended by all instructors and students who will be flying on that particular shift. By doing this, it is ensured that everyone has looked at the weather prior to their flight. The only exception is if a student is going on a Transport Canada flight test where the student will be graded by an examiner for checking weather.
  • Recurrent upset training for instructors – All instructors to go through upset training in Seneca College flight training devices to assist them in any given circumstances where they need to take control of an aircraft and recover from an unusual attitude. This training is done with certain flight instruments failed.
  • Night flying ground briefing for instructors – A recurrent training session regarding night flying.
  • Weather briefing for instructors – A recurrent training session regarding weather hazards with a focus on icing.
  • Briefing on spatial disorientation for instructors – A recurrent training session reviewing different types of illusions and preventative measures.
  • Expanded indoctrination training for new instructors – New instructors to have an expanded indoctrination checklist they complete when they start teaching at the college.
  • The Seneca College aviation training program is broken up into different phases. An expanded training program is being developed for instructors who start training in a new phase of the program based on their past experience.
  • Stand by attitude indicators to be installed in aircraft – The plan is for standby attitude indicators to be installed in all aircraft that require them. This is in the event there is a failure of the primary attitude indicator; the standby attitude indicator can be used to aid in flying the aircraft.

Seneca College has instituted the limits shown below for single engine at night operations:

  • All night flying is to be conducted in VFR weather only.
  • Instrument or IFR training may be conducted at night in VMC only.
  • VFR flight plans are to be filed at night outside of the circuit (no IFR filing even in VMC).
  • Reported and forecast visibility shall not be less than 6 statute miles. Authorized ceiling remains as per its Operations Manual Section 2.6.
  • There shall be no visible or forecast precipitation in the area of operation when flying in temperatures of 5 °C or colder (at operating altitude).
  • No observers are permitted on board training flights at night i.e. 1 student and 1 instructor only. Combined lessons where more than one student participates will be restricted to daytime flying.
  • Any exceptions to this policy will be at the sole discretion of the CFI or delegate on a case by case basis.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 01 February 2012.


Appendix A – RNAV Runway 33 Approach Chart

Appendix A - RNAV Runway 33 Approach Chart

NOT FOR NAVIGATIONAL PURPOSES

Appendix B – Graphical Area Forecast

Appendix B - Graphical Area Forecast (GFA) for the occurrence area valid from 1800 (coordinated universal time) on 18 November 2010,  Icing, Turbulence & Freezing level

Appendix B - Graphical Area Forecast (GFA) for the occurrence area valid from 1800 (coordinated universal time) on 18 November 2010,  Clouds & Weather

Appendix B - Graphical Area Forecast (GFA) for the occurrence area valid from 0000 (coordinated universal time) on 19 November 2010,  Icing, Turbulence & Freezing level

Appendix B - Graphical Area Forecast (GFA) for the occurrence area valid from 0000 (coordinated universal time) on 19 November 2010,  Clouds & Weather

Appendix B - Graphical Area Forecast valid from 0600 (coordinated universal time) on 19 November 2010,  Icing, Turbulence & Freezing level

Appendix B - Graphical Area Forecast (GFA) for the occurrence area valid until 0600Z on 19 November 2010,  Clouds & Weather

  1. All times are Eastern Standard Time (Coordinated Universal Time minus 5 hours). ↑
  2. All altitude values are estimated based on radar return data which has a plus or minus 50 feet variance. ↑
  3. Radar displays ground speed. The indicated airspeed was calculated based on wind aloft data. ↑
  4. All tracks are true unless stated otherwise. ↑
  5. There was an additional 33.4 hours of instrument instruction recorded in Seneca’s FRASCA instrument simulator which had not been transcribed into his personal log book. ↑
  6. RNAV GNSS – Area Navigation Global Navigational Satellite Systems. ↑

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Aviation Reports – 2011 – A11W0070

| Transportation Safety Board Reports | March 15, 2012

Transportation Safety Board of Canada

Aviation Reports – 2011 - A11W0070

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Loss of Control – Collision with Water
Campbell Helicopters Ltd.
Bell 212 C–FJUR
Slave Lake, Alberta, 12 nm W
20 May 2011

Report Number A11W0070

Synopsis

The Campbell Helicopters Ltd. Bell 212 (registration C–FJUR, serial number 30728) was conducting water bucketing operations in support of forest fire suppression services in the vicinity of Slave Lake, Alberta. At approximately 1449, Mountain Daylight Time, during an approach to Lesser Slave Lake to pick up water, the helicopter crashed into the lake on its right side. The helicopter sustained major damage. There was no post–crash fire. The pilot, who was the sole occupant, was fatally injured. The emergency locator transmitter signal was not detected by search and rescue until after the helicopter was removed from the water.

Other Factual Information

History of Flight

The Bell 212 helicopter (C–FJUR) departed from the Slave Lake airport at 1323, 1 proceeded to the Lesser Slave Lake shoreline near the Canyon Creek hamlet, and began water bucketing operations. Water pickups were made near the south shore of the lake and drops were made on a fire approximately 0.8 nautical miles (nm) south of the shoreline. On its 12th pickup, while on short final, the helicopter abruptly descended forward, in a near–level attitude, to within several feet of the water surface. Subsequently, the helicopter climbed to approximately 100 feet above the lake surface and then rolled rapidly to the right and descended vertically into the water.

Within approximately 3 to 4 minutes, municipal fire fighters in the vicinity entered the water and removed the pilot from the wreckage. The municipal fire fighters administered first aid until emergency medical personnel arrived. However, the pilot succumbed to head injuries as a result of the impact.

Aircraft

The Bell 212 is a twin–engine, single main–rotor helicopter that can carry up to 14 passengers with 1 pilot. Records indicate that the helicopter was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The helicopter had no known deficiencies before the occurrence flight. The weight and centre of gravity were within the prescribed limits and there was sufficient fuel on board to complete the flight.

The helicopter was equipped with a Skytrac satellite tracking system that transmitted position reports every 2 minutes that were stored in the Alberta Sustainable Resource Development (ASRD) database. In addition, ASRD requires pilots to make position reports every 30 minutes.

Water Pickup Location

In calm wind conditions, water can take on a glassy, mirror–like appearance which significantly reduces a pilot’s depth perception. If a pilot does not have adequate visual references when flying over glassy water surfaces, difficulties may be encountered in judging height above water and gauging forward speed. The TSB has investigated numerous occurrences where glassy water was either a causal or contributing factor. 2

To help ensure adequate visual references to safely manoeuvre a helicopter during a water pickup, it is common practice to make pickups as close to shore as possible. This allows the pilot to use the shoreline and surrounding terrain to help judge height above the water as well as the rate of closure during the approach.

The pilot carried out pickups between 300 feet and 1050 feet from the shoreline. The investigation examined the water pickups conducted by another pilot. On average, the other pilot’s pickup location was between 100 feet and 200 feet from the shoreline. The occurrence pilot had been advised by another company pilot to make his pickups as close to shore as possible due to the smoke and glassy water conditions in order to maximize visual references.

Meteorological Information

The aviation routine weather report (METAR) issued for the Slave Lake Airport at 1400 reported winds 290° true (T) at 6 knots, visibility 3 statute miles (sm) in smoke, a few clouds at 7100 feet above ground level (agl) , temperature 14°C, dew point 11°C and an altimeter setting of 30.13 inches of mercury (in. Hg). The METAR issued at 1500 reported winds 300°T at 9 knots, visibility 4 sm in smoke, sky clear, temperature 18°C, dew point 11°C and an altimeter setting of 30.11 in. Hg.

The investigation determined that visibility in the fire area, approximately 12 nm from the Slave Lake Airport, was variable: from 0.5 sm to 3 sm in smoke. The wind was calm and the lake surface was glassy.

Water Bucketing Operations

The helicopter was configured to carry external loads on a hook mounted on the underside of the helicopter’s belly. This belly hook was rated for a maximum load of 5000 pounds. A 100–foot long line attached to the belly hook was being used with a 350 imperial gallon water bucket. When full of water, the combined weight of the long line and the water bucket was approximately 3650 pounds. The bucket was 23 feet long when suspended, for a total long line length of approximately 124 feet.

The water bucket is electrically opened by a button located on the collective control.

The belly hook can be released either electrically or manually. A button on the cyclic control stick is the primary release. To arm this electrical release, the pilot must select the hook release switch, which is guarded and located in the overhead console. The manual release is designed as a backup in an emergency, if the electric release fails. To activate the manual release, the pilot must take one foot off the anti–torque control pedals and use it to push the release pedal.

Bell 212 Flight Manual Supplement (BHT–212–FMS–3) directs pilots to arm the hook for take–off, disarm it for in–flight operations (i.e., cruise), and arm it before final approach. Arming the hook prior to take–off and final approach allows the pilot to quickly release the load should a problem arise during a critical phase of flight. Disarming the hook during cruise reduces the risk of an inadvertent release.

In many cases, dropped loads are the result of pilots accidently triggering the electrical release. As previously established in TSB occurrence A09P0249, many pilots choose to fly with the belly hook electrically disarmed to reduce the risk of an inadvertent load release.

Pilot Competencies for Helicopter Wildfire Operations

The Canadian Interagency Forest Fire Centre (CIFFC) is composed of agencies responsible for forest firefighting from all provinces and territories. CIFFC has a mandate to gather, analyze and disseminate fire management information to ensure resources are shared cost–effectively. In addition, it actively promotes, develops, refines, standardises and provides services to member agencies to improve forest fire management in Canada.

After the 2007 Helicopter Association of Canada (HAC) convention, a number of these agencies (notably Alberta, British Columbia, and Saskatchewan) and the HAC agreed that pilot eligibility for roles in wildfire suppression should be based on a task–competency model rather than relying solely on flight hours. In 2010, the HAC, through its Air Taxi Committee subgroup, the Pilot Qualifications Working Group, developed a document titled Pilot Competencies for Helicopter Wildfire Operations – Best Practices Training and Evaluation.

Alberta Sustainable Resource Development (ASRD) developed an operating handbook for pilots in 2010 and issued an amended version, the 2011 Pilots Handbook, the following year. The 2011 Pilots Handbook endorses the use of qualifications and training competencies identified in the HAC document “Pilot Competencies for Helicopter Wildfire Operations”.

At the time of the occurrence, Campbell Helicopters was operating C–FJUR under a contract with the ASRD. Although it was not required to meet the 2011 standards because the contract was signed before the new standards came into effect, Campbell Helicopters did apply these standards for its pilot checks at the start of 2011 season.

Wreckage and Impact Information

The helicopter was found on its right–hand side in Lesser Slave Lake at 55° 22.154 N and 115° 03.319 W. The helicopter was approximately 290 feet from the southern edge of the lake and oriented parallel to the shore, facing west (see Photo 1).

Photo 1. Helicopter Crash Location
Photo 1. Helicopter Crash Location

An examination of the wreckage revealed that the engines were developing high power at the time of impact. The collective was found in the full up position, and all collective connections to the engines were consistent with full power being requested. There was no indication of any system malfunction prior to the occurrence.

The helicopter experienced extensive hydroforming of the right–hand sub–floor panels as well as the right–side roof and sliding door. In addition, the 2 left attachment points on the tail boom failed due to overload toward the right side of the helicopter. This is consistent with the helicopter landing with a high downward velocity on its right side at impact.

The pilot seat had little structural damage. All the seat safety harness systems were tested following the occurrence and found to be serviceable. However, the left side lap belt attachment point had torn loose as a result of the impact. There was no shock–absorbing mechanism in the seats. It was also determined that the pilot was not wearing the available shoulder harnesses at the time of impact.

These harnesses are designed for use when the pilot is sitting upright in a normal flight position. It is common practice for pilots not to wear the shoulder straps while long–lining because it can hinder upper body movement to the bubble window. An aftermarket vertical reference seat is available that permits pilots to lean without removing their shoulder straps.

The electric release for the belly hook was found in the disarmed position. The long line, which was found disconnected from the belly hook, was loosely strung in a more or less straight line from the bucket toward the helicopter at approximately the same distance from the shoreline. The long–line top–end clevis and the belly hook showed no indications of damage and the water bucket dump valve was in the normal closed position for a pickup. The water bucket was tested on another company helicopter, and functioned normally.

Emergency Locator Transmitter

A signal was not received from the emergency locator transmitter (ELT) after impact. However, once the helicopter was lifted out of the water during recovery, the signal was detected by the COSPAS–SARSAT satellite system.

The 406 Mhz ELT is designed to transmit a distress message repeatedly. The repetition period is randomized around a mean value of 50 seconds to ensure that no 2 beacons have coincident data bursts. The distress message is not retransmitted until at least 1 repetition period has elapsed, making it possible to differentiate between legitimate distress messages and messages sent by error during maintenance or testing. 3

When an aircraft crashes into water, there is a strong possibility that the fixed ELT antenna will be submerged before the 50–second delay has elapsed. If the antenna is under water, an ELT signal may be severely attenuated and may not be detected.

Pilot

The pilot held an Airline Transport Pilot Licence – Helicopter, validated by a flight medical on 18 April 2011. Available records indicate that the occurrence pilot had between 4900 to 5500 total flight hours, of which about 200 flight hours were on the Bell 212. The license was endorsed for 7 different helicopter types. In April 2011, the pilot participated in Bell 212 training at Campbell Helicopters and passed the company Pilot Proficiency Check (PPC). The training provided by Campbell Helicopters included the HAC–developed and ASRD–approved pilot competencies for helicopter wildfire operations.

Prior to 2006, the pilot had accumulated approximately 500 hours carrying out external load operations, of which approximately 20 were long line work. He had no external load experience with any of the 3 operators with whom he had been employed since 2006. However, on the Canadian Interagency Forest Fire Centre (CIFFC) Pilot Directory, the pilot had listed 500 hours slinging, 50 hours long lining and 50 hours water bucketing. This discrepancy could not be reconciled.

Flight Helmets

The pilot, who was not wearing a flight helmet, received severe head injuries during the impact sequence. The pilot’s flight helmet was found inside its bag at the rear of the helicopter cabin.

The occurrence pilot was not required by Campbell Helicopters to wear a helmet, nor is there a regulation requiring helicopter pilots to wear head protection.

The second most frequently injured body region in survivable helicopter crashes is the head. 4 According to United States military research, the risk of fatal head injuries can be as high as 6 times greater for helicopter occupants not wearing head protection. 5 The effects of non–fatal head injuries range from momentary confusion and inability to concentrate to full loss of consciousness. 6 Incapacitation can compromise a pilot’s ability to escape quickly from a helicopter and assist passengers in an emergency evacuation or survival situation.

In 1988, the National Transportation Safety Board (NTSB) reviewed 59 emergency medical services (EMS) aviation accidents between 11 May 1978 and 03 December 1986. This study resulted in NTSB‘s recommendations A–88–009 to the FAA and A–88–014 to the American Society of Hospital Based Emergency Aeromedical Service asking them to require that flight crew and medical personnel wear protective helmets, and encourage them to do so, to reduce the chance of injury and death.

Transport Canada recognized the safety benefits of using head protection in its 1998 Safety of Air Taxi Operations Task Force (SATOPS) 7 report in which it committed to implementing the following recommendation:

Recommend Transport Canada continue to promote in the Aviation Safety Vortex 8 newsletter the safety benefits of helicopter pilots wearing helmets, especially in aerial work operations, and promote flight training units to encourage student pilots to wear helmets.

In addition, SATOPS directed the following recommendation to air operators:

Recommend that helicopter air operators, especially aerial work operators, encourage their pilots to wear helmets, that commercial helicopter pilots wear helmets and that flight training units encourage student helicopter pilots to wear helmets.

The TSB has documented a number of occurrences 9 where the use of head protection likely would have reduced or prevented the injuries sustained by the pilot.

TSB investigation A09A0016 found that despite their well–documented safety benefits, and the challenging nature of helicopter flying, the majority of helicopter pilots continue to fly without head protection. Likewise, that investigation also found most Canadian helicopter operators do not actively promote, or require, the use of head protection by company pilots.

In recognition of the benefits of head protection, on 27 June 2011, a resolution passed by the HAC Board of Directors stated that:

HAC strongly recommends to its Operator–Members that they should promote the use of helmets for helicopter flight crew members under all operational circumstances which permit their use. HAC also points out, however, that certain pilot/aircraft type configurations may preclude safe helmet use.

The following TSB Laboratory reports were completed:

LP082/2011 – Examination of Servo Cylinder Fracture
LP077/2011 – Annunciator Panel Examination

Analysis

There was no indication that an aircraft system malfunction contributed to this occurrence. As a result, the analysis will focus on the operational and environmental factors which contributed to the occurrence and the injuries sustained by the pilot.

The investigation determined that the occurrence pilot was conducting water pickups at a considerable distance from shore over glassy water. The glassy water conditions that would have made depth perception difficult were compounded by the lack of visual references due to the distance from shore. The helicopter had not yet come into the hover when the water bucket inadvertently entered the water. This resulted in a violent pull rearward and to the left, causing it to descend and roll to the right. The pilot likely overestimated the helicopter’s altitude while on final approach, due to glassy water conditions and a lack of visual references, which led to the water bucket inadvertently entering the water.

The helicopter then descended to within several feet of the water. The pilot’s subsequent attempt to recover would have required both hands on the controls, precluding arming the belly hook’s electrical release. When the helicopter climbed, it is likely that the combination of the long–line tension, helicopter movement, and high power setting caused the helicopter to roll to the right and descend quickly into the water.

Because the belly hook was electrically disarmed, the pilot’s ability to jettison the water bucket was limited. It is possible that the pilot released the belly hook using the manual release located between the pedals using one of his feet or it may have been released on impact. Irrespective of how the hook was released, the helicopter impacted the water before the pilot was able to regain control.

The pilot was not wearing his flight helmet, which contributed to the severity of his head injuries, given that his upper body was not restrained by a shoulder harness (shoulder harnesses can hinder upper body movement to the bubble window). Despite the recognized benefits of head protection, there is no requirement for helicopter pilots to wear helmets. The lack of regulation or policies requiring helicopter pilots to wear helmets places them at greater risk of incapacitation due to head injuries incurred during ditching or a crash.

If an aircraft crash occurs over land, an ELT that survives a crash will normally transmit at full strength after the required 50–second delay. In this case, the fixed ELT antenna was submerged within the 50 seconds. As a result, it is probable that the ELT signal was severely attenuated and could not be detected by the COSPAS–SARSAT satellite system. It was not until the wreckage was recovered that the signal was received. As long as ELTs are not set up to transmit a signal immediately, water attenuation of useable ELT signals from submerged aircraft will continue to pose a risk of an ELT signal not being received and SAR resources not being deployed soon enough.

Findings as to Causes and Contributing Factors

  1. The pilot likely overestimated the helicopter’s altitude while on final approach, due to glassy water conditions and a lack of visual references, which led to the water bucket inadvertently entering the water before the helicopter was established in the hover.
  2. The helicopter was pulled violently rearwards and to the left, as a result of the water bucket entering the water. This caused the helicopter to descend and the pilot to lose control.
  3. The helicopter was being operated with the belly hook electrically disarmed, limiting the pilot’s ability to jettison the water bucket before losing control.
  4. The pilot was not wearing his flight helmet, which contributed to the severity of his head injuries, given that his upper body was not restrained by a shoulder harness.

Findings as to Risk

  1. The lack of regulation or policies that requires helicopter pilots to wear helmets places them at greater risk of incapacitation from head injuries incurred during ditching or a crash.
  2. Without an immediate signal being transmitted from an ELT installation, water attenuation of useable ELT signals from submerged aircraft will continue. This increases the risk of an ELT signal not being received and SAR resources not being launched in a timely manner.

Other finding

  1. Inconsistencies in recorded flight hours were noted in the pilot’s external load experience.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 24 January 2012.


  1. All times Mountain Daylight Time (Coordinated Universal Time minus 6 hours) unless otherwise stated. ↑
  2. A02P0256, A05P0262, A06C0131, A06W0106, A90W0206. ↑
  3. Specification for COSPAS–SARSAT 406 Mhz Distress Beacons, C/S T.001, Issue 3 – Revision 12, October 2011. ↑
  4. Shanahan, D., & Shanahan, M. (1989). Injury in U.S. Army Helicopter Crashes October 1979 – September 1985. The Journal of Trauma, 29(4), 415–423. ↑
  5. Crowley, J.S. (1991). Should Helicopter Frequent Flyers Wear Head Protection? A Study of Helmet Effectiveness. Journal of Occupational and Environmental Medicine, 33(7), 766–769. ↑
  6. Retrieved from http://www.braininjury.com/injured.shtml on 31 August 09. ↑
  7. Transport Canada (1998). SATOPS Final Report, TP 13158. ↑
  8. The Aviation Safety Vortex newsletter has now been discontinued, but is combined with the Aviation Safety Letter. ↑
  9. TSB Occurrences: A98W0086, A95A0040, A94W0147, A94Q0101, A93Q0237, A91W0046, A87P0089, A87P0025, A87P0023, A86C0060, A85P0011, A05P0103, A95P0215, A99P0070 and A09A0016. ↑

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Aviation Reports – 2010 – A10C0214

| Transportation Safety Board Reports | February 17, 2012

Transportation Safety Board of Canada

Aviation Reports – 2010 – A10C0214

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Engine Power Loss and Autorotative Landing
Forest Helicopters Inc.
Eurocopter AS 350 B2 (Helicopter), C–FORS
Pickle Lake, Ontario, 6 nm northeast
12 December 2010

Report Number A10C0214

Synopsis

On 12 December 2010, during daylight hours, the Forest Helicopters Inc. Eurocopter AS 350 B2 helicopter (registration C–FORS, serial number 4001) was conducting slinging operations approximately 6 nautical miles northeast of the Pickle Lake Airport, Ontario. The pilot had picked up a load of fuel barrels with a longline and was transitioning into forward flight. At low airspeed, and approximately 250 feet above ground level, the helicopter’s engine lost power. The pilot jettisoned the load and attempted an autorotative landing. The helicopter struck the ground in a level attitude and one of the main rotor blades severed the helicopter’s tail boom. The pilot was not injured and was able to exit the aircraft without assistance. The helicopter was substantially damaged. There was no post‑crash fire and the emergency locator transmitter did not activate. The accident occurred at 0800 Central Standard Time.

Factual information

History of flight

The Eurocopter AS 350 B2 helicopter (helicopter) was being operated in support of mining operations from a staging area located approximately 6 nautical miles (nm) northeast of the Pickle Lake Airport (CYPL). When not in use, the helicopter remained outside at the staging area. The helicopter was equipped with winter covers for both the rotor head and engine and transmission area, along with portable electric heaters. On the morning of the occurrence, the pilot removed the winter covers and electric heaters and prepared the helicopter for use. The pilot conducted a visual inspection of the helicopter. No precipitation had fallen overnight and the helicopter was free of contamination.

The pilot had fuelled the helicopter the day before to approximately 50% of its maximum fuel capacity, 1 sufficient for the planned morning flights. The helicopter flight manual’s cold weather operation section, states: “Do not bleed the fuel system under a temperature equal to or lower than -10°C where valve seals prove inefficient.” The morning of the occurrence, the ambient temperature was -29°C and the fuel system was not drained.

The pilot started the helicopter, and after a normal start and warm up, loaded the drill crew and flew to the first drill site located approximately 1.4 nm to the northwest of the staging area. The pilot dropped off the first drill crew and continued on to the second drill site located approximately 2.4 nm northeast. The pilot dropped off the second drill crew and returned to the first drill site to pick up the first drill crew. The pilot then returned to the staging area to drop off the first drill crew and pick up 3 fuel barrels, which were to be moved to a cache site. The fuel barrels had been placed in slings and a 100–foot longline was positioned on the ground in preparation for the move. After the first drill crew had disembarked, one of the drill crew members hooked the longline to the helicopter. The pilot then moved the helicopter closer to the fuel drums and the drill crew member hooked the longline to the drum slings.

The staging area was surrounded by 70–foot trees. The pilot began a vertical lift with the 3 barrels in order to clear the trees. Once the barrels were above the trees, the pilot began to transition into forward flight. At approximately 250 feet above ground level, with approximately 40 knots forward airspeed, the engine suddenly began to spool down. The engine gas generator speed (Ng) and main rotor speed (Nr) gauges rapidly decreased. The pilot immediately lowered the collective control, applied a forward cyclic control input to gain airspeed, and released the slung load.

The helicopter descended rapidly and just prior to ground contact, the pilot raised the nose of the helicopter to reduce forward speed and attempted to run the tail stinger on the ground to slow the descent and reduce the impact force. The helicopter struck the ground with some forward momentum. As a result of the impact, one of the main rotor blades struck and severed the tail boom (see Photo 1). The helicopter remained upright and slid forward approximately 60 feet before coming to rest. The emergency locator transmitter (ELT) did not activate as the deceleration forces were less than those required to activate its internal multi–axis g–switches. The pilot, who was wearing a 4–point harness and helmet, was able to exit the aircraft uninjured. The Arriel 1D1 engine had stopped running by the time the helicopter made contact with the ground. The engine had been running continuously from initial start–up until it lost power. The total flight time was approximately 37 minutes. There were no abnormal engine or cockpit indications prior to the engine power loss.

Photo 1. Occurrence Aircraft
Photo 1. Occurrence Aircraft ↑

Pilot information

Records indicate that the pilot was certified and qualified for the flight in accordance with existing regulations. The pilot held a commercial helicopter pilot licence valid for daylight visual flight rules and a category 1 medical certificate valid until 01 March 2011. The pilot had accumulated approximately 4100 total flight hours prior to the occurrence with approximately 1100 flight hours on the accident aircraft type. There was nothing found to indicate that the pilot’s performance was degraded by physiological factors.

Weather

The 0800 2 aviation routine weather report for CYPL was as follows: wind 280° true at 3 knots, visibility 15 statute miles with clear skies, temperature -29°C, dew point -33°C, and altimeter setting 30.33 inches of mercury.

Aircraft information

Records indicate that the helicopter was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The total time on airframe was 3412.8 hours and the total time on the engine was 1278.9 hours. On 22 October 2010, the helicopter underwent a 100–hour inspection, approximately 40 flight hours prior to the occurrence. The helicopter had been experiencing an intermittent engine starting problem and several engine fuel system components were replaced. On 07 September 2010, the fuel pressurizing valve was replaced.

On 22 October 2010, the ignition box and start drain valve were replaced. On 23 October 2010, the start injector electro–valve and ignition cables were replaced and the start injectors were re‑shimmed. On 29 November 2010, approximately 10 hours prior to the occurrence, the hard starting problem continued and fuel was noted coming from the fuel control unit’s (FCU) overboard drain line during system purge with the boost pumps on. However, the leakage stopped when the engine was running. The overboard leakage was within acceptable limits but the FCU was replaced with a rental unit to troubleshoot the starting issue.

The installation of the rental FCU did not fix the starting problem, and the original FCU was reinstalled. Subsequently, the engine start injectors were replaced and the engine start problem seemed to be resolved. An auto–ignition system is not available for this engine, nor is it required by regulation.

Wreckage examination

The helicopter was removed from the site and transported to the operator’s base in Kenora for examination. The helicopter was kept outside in below–freezing temperatures until it could be examined by a team consisting of representatives from the TSB, the operator, and the engine and airframe manufacturers. The engine air inlet and inlet FDC/Aerofilter barrier air filter (installed under Supplemental Type Certificate (STC) SR00811SE) were examined and found to be free of major obstruction. Other than the visual examination, no further testing of the filter was conducted. Part of the FDC/Aerofilter STC included the installation of an engine alternate air door and a low inlet pressure warning light system. The warning light is designed to illuminate if a filter blockage occurs. The low inlet pressure warning system was tested and found to operate normally. There was no indication that the light had illuminated during the occurrence.

The helicopter was equipped with a Eurocopter Canada Limited (ECL) STC anti–icing fuel filter and the standard Le Bozec airframe fuel filter equipped with a FAA/PMA Puroflow/WFC filter cartridge. The fuel system was examined and no restrictions or contamination were found in the fuel tank, fuel lines, or inline fuel filters. The fuel level was determined to be about 40%. The fuel shutoff lever was witness–wired in the open position. The fuel control lever was in the Stop detent position, where it had been moved by the pilot prior to leaving the helicopter. The engine throttle, fuel control lever, anticipator and engine FCU rigging were checked. There were no anomalies noted. Both fuel pumps were tested and operated normally.

A pressure test of the system was carried out with no leaks present. Fuel samples were taken and were found to be clear and bright. The fuel was subsequently tested and found to meet the Jet A–1 specifications for density, flash point, water content, freezing point and distillation properties. The effects of the cold weather operation on the occurrence, if any, could not be determined.

The engine and engine fuel control components were removed from the helicopter and taken to the engine manufacturer’s facility in Grand Prairie, Texas, for testing and examination. The engine was installed on a test bed and run successfully. The engine met all performance criteria with no anomalies noted. The engine fuel control unit, start solenoid valve, start drain valve, main drain valve and pressurizing valve were removed from the engine and bench checked. No faults were found that would have resulted in an engine flameout.3 The fuel control unit was disassembled and no internal anomalies were noted.

Fuel system testing

The helicopter was re–examined and the complete airframe fuel system was removed and taken to the TSB Central Region wreckage examination facility for further examination and testing (see Figure 1). For test purposes, the fuel lines were changed with clear plastic lines of the same internal diameter to allow for an unobstructed view of the fuel flow through the system.

Figure 1. Fuel System
Figure 1. Fuel System ↑

A valve was positioned aft of the firewall fuel shut–off valve to simulate fuel purge and flight conditions. The purge, cruise and maximum power flow rates were obtained from data acquired through testing of the engine and engine fuel components at the Turbomeca facility in Grand Prairie, Texas. A variable DC power supply was used to power the electric fuel boost pumps.

The airframe fuel filters were removed and reinstalled to simulate servicing of the fuel system. The boost pumps were turned on and the fuel system was bled in accordance with instructions contained in the Aircraft Maintenance Manual (MM), Section 28.00.00.302. The fuel flow was set to the purge flow rate and once the flow stabilized, the pumps were shut off. A large quantity of air that had not been bled out of the system during the purge event remained in the line, between the 2 fuel filters. The flow rate was increased to the cruise and maximum power settings and air slowly bled past the fuel filters. With rapid flow adjustments, larger quantities of air bled past the filters.

The test was carried out for 37 minutes to simulate the occurrence flight. At the end of the test, a small quantity of air was observed in the fuel line upstream of the Le Bozec airframe filter.

On–ship testing

On–ship testing was carried out on another company helicopter equipped with the same fuel system configuration as the occurrence helicopter. The fuel line connecting the ECL filter to the Le Bozec filter was removed and replaced with clear plastic tubing to allow for a view of the fuel flow through the system. The airframe fuel filters were removed and reinstalled. Then, the system was bled in accordance with MM, Section 28.00.00.302. After these procedures were completed, the same quantity of air was observed in the fuel line as was found during the tests conducted on the occurrence aircraft’s fuel system.

In preparation for an engine run, the boost pumps were turned on for 30 seconds, as per Section 4, Normal Procedures, in the Rotorcraft Flight Manual (RFM), before the start button was pressed to facilitate purging of the FCU. The engine started normally and after the Ng stabilized, the fuel pumps were shut off in accordance with MM, Section 28.00.00.301 which requires that fuel system testing be done after maintenance work to ensure that no engine flameout or instability occurs, which could indicate that some air was drawn into the fuel system.

With the boost pumps OFF, air was rapidly and sporadically drawn out of the ECL filter. This air entered the Le Bozec filter. Some minor engine surging occurred, but the engine continued to run. After approximately 2 minutes, the pumps were turned back ON and the engine regained smooth operation. The engine was run for another 3 minutes with the fuel flow control lever in the flight detent position. No abnormal indications were noted and flight would normally be initiated at this time. However, the engine was shutdown at that point. During the later stages of engine spool down, a small bubble of air appeared at the inlet of the Le Bozec filter. After the engine came to a complete stop, the fuel pumps were shut off. The bubble of air was then rapidly drawn back out of the Le Bozec filter inlet until approximately 8 inches of air was visible in the line (see Appendix A).

Air introduction

The fuel boost pumps are equipped with check valves that incorporate bleed ports to allow for pressure in the fuel lines to be bled off after engine shutdown. If the fuel system is opened, such as during filter servicing, air can be drawn into the system as fuel is returned to the tank by gravity through the check valve bleed port.

Testing also showed that air can enter the system if the fuel filters are drained with the boost pumps off. The flight manual supplement associated with the STC ECL fuel filter stipulates that the ECL filter is to be drained with the boost pumps on. When the ECL filter was drained with the boost pumps on during testing, air was not drawn into the system. In the case of the Le Bozec filter, the RFM and maintenance manual make no reference to a daily draining procedure.

The Component Maintenance Manual for the Le Bozec P/N 432B12–4 filter references draining the water at the bottom of the filter bowl by the hand operated drain valve when the flow of the fuel is stopped.  Consultation with industry personnel shows that there are varying views on the draining practice for this filter.4 Some operators drain the filter on a daily, pre–flight basis, with the boost pumps on, others drain it with the boost pumps off, and some do not drain the filter at all.

The third way that air can enter the fuel system is past a leaking FCU NTL5 or Ng drive fuel‑pump seal. Following this occurrence, hard starting problems were encountered on another company helicopter. While troubleshooting, fuel leakage was noted coming out of the FCU overboard drain line during system purge. This fuel leakage is similar to what was experienced on C–FORS prior to the occurrence.

The source of the leak was believed to be either the FCU NTL or Ng drive fuel–pump seal. When stationary, air was being drawn through the FCU drain lines by the reverse flow of fuel, and back to the aircraft fuel tank. The fuel pump check valves were replaced with non–return valves. This stopped the reverse fuel flow and air from being drawn into the fuel system. The hard starting problems did not recur.

Engine flameouts

The engine’s ignition system is only in operation during the starting sequence. Once started, combustion is continuous and self–sustaining as long as the engine is supplied with the proper fuel–to–air ratio. If the rich limit of the fuel–to–air ratio is exceeded in the combustion chamber, the flame will extinguish. This condition is referred to as a rich flameout. It generally results from very fast engine acceleration, where an overly rich mixture causes the fuel temperature to drop below the combustion temperature. It also may be caused by insufficient airflow to support combustion, which may occur as a result of a blocked engine inlet or inlet filter.

An interruption of the fuel supply can also cause an engine to flame out. This may be due to prolonged unusual attitudes, a malfunctioning fuel control system, and blocked fuel supply, air introduction into the fuel delivery system, turbulence, icing or fuel exhaustion.

The Arriel 1D1 engine is not equipped with an auto–ignition system, so if a flameout occurs, the engine will not automatically restart.

Previous engine power losses

On 19 December 2010, concurrent with this investigation, the National Transportation Safety Board (NTSB) began an investigation of an AS 350 B2 helicopter (registration N549AM, serial number 4339) that had an engine power loss event in LaMonte, Missouri, USA (NTSB Accident No. CEN11LA118). The information surrounding the 2 occurrences was shared between the TSB and NTSB to facilitate common testing. In that occurrence, the Turbomeca Arriel 1D1 engine was run with no anomalies noted. The fuel systems of the 2 accident helicopters are identical with the exception of the ECL anti–ice filter. Testing of the fuel system carried out in support of the NTSB investigation produced similar results in regards to air introduction and difficulty associated with purging the system of air.

In order to address difficulties reproducing reported power loss events, the manufacturer had previously developed a troubleshooting checklist for operators to follow in the event of a power loss. That checklist was issued by Turbomeca, on 08 June 2005, as service letter 2338/05/AR1D/68, titled, “In–flight engine power loss”.

On 01 January 2009, Eurocopter issued technical support document 2030–I–00. This document, which was produced as a result of cases of engine flameout or damage occurring shortly after take–off, outlined precautions to follow when conducting cold weather operations in snow or rain.

The following TSB Laboratory report was completed:

LP 198/2010 – Fuel Analysis

This report is available from the Transportation Safety Board of Canada upon request.

Analysis

Testing of the engine and its fuel system could not identify a mechanical reason for the engine power loss. A blockage in the air inlet or fuel delivery system could cause an engine to flame out, but no such blockage or contamination was noted. Testing of the fuel system showed that air can become entrapped in the fuel system which could not be bled out by normal maintenance action prior to flight. The analysis will therefore examine the role that air entrapment may have played in this occurrence.

The investigation determined that air can be introduced into the fuel system through either a leaking FCU NTL or Ng drive fuel–pump seal, routine maintenance of the fuel system, or by draining the fuel filters with the boost pumps off. In this occurrence, the likely source of the air was a leaking FCU NTL or Ng drive fuel–pump seal which was identified during the hard start troubleshooting problems approximately 10 hours prior to the occurrence. However, the significance of this leakage, in combination with fuel boost pump check valves that incorporate bleed ports, was unknown at the time of the troubleshooting and the FCU was reinstalled on the helicopter.

An engine flameout likely occurred as a result of an interruption in fuel flow due to the entrapment of air in the fuel system. In response to the engine power loss, the pilot attempted to carry out an autorotation to the ground. However, the engine power loss occurred at an altitude from which a safe landing was not assured.

Some operators have adopted the informal practice of draining the Le Bozec airframe filter with the boost pumps off. The RFM and MM make no reference to a daily draining procedure for the Le Bozec airframe filter. On helicopters equipped with boost pump check valves that incorporate bleed ports, the practice of draining the Le Bozec fuel filter with the boost pumps off may inadvertently introduce air into the aircraft’s fuel system.

The Arriel 1D1 engine is not equipped with an auto–ignition system, nor is it required by regulation. On helicopters without an auto–ignition system, if a flameout occurs, there may be insufficient time to attempt an engine relight.

Findings as to causes and contributing factors

  1. A leaking FCU NTL or Ng drive fuel–pump seal, in combination with fuel boost pump check valves that incorporate bleed ports, likely allowed air to be introduced into the fuel system.
  2. The engine lost power, likely as a result of a flameout caused by an interruption in fuel flow due to entrapment of air in the fuel system.
  3. The engine power loss occurred at an altitude from which a safe landing was not assured.

Findings as to risk

  1. On helicopters equipped with boost pump check valves that incorporate bleed ports, the practice of draining the Le Bozec fuel filter with the boost pumps off may inadvertently introduce air into the aircraft’s fuel system, thereby increasing the risk of an engine flameout.
  2. After routine fuel filter maintenance, the fuel system bleeding procedure does not ensure the system is completely purged of air, thereby increasing the risk of an engine flameout.
  3. The Arriel 1D1 engine is not equipped with an auto–ignition system. Therefore, if a flameout occurs there may be insufficient time to attempt an engine relight.

Other findings

  1. The effects of the cold weather operation on the occurrence, if any, could not be determined.
  2. Limited testing did not establish that the FDC/Aerofilter barrier air filter, ECL anti–icing fuel filter, or FAA/PMA fuel filter cartridge had any adverse effect on the operation of the engine in this occurrence.

Safety action taken

Due to similarities between this occurrence and the concurrent NTSB investigation, Eurocopter France initiated a test program to see if air that had been introduced into the fuel system could result in engine operating difficulties. The tests were conducted in conjunction with the engine manufacturer Turbomeca, the airframe filter manufacturer Le Bozec and the French accident investigation bureau BEA (Bureau d’Enquêtes et d’Analyses). The tests were initiated in the spring of 2011with further testing of the airframe fuel filter conducted in the fall of 2011. Testing of the engine for air ingestion is planned for late 2011 with a full analysis in progress.

On 26 July 2011 Eurocopter released Information Notice No. 2351–I–28 informing operators of AS350 B, BA, BB, B1, B2 and D models of the possibility of air being introduced in the fuel system by activating the drain located at the bottom of the airframe filter unit assembly. Eurocopter reminded operators that the drainage of the fuel filter is not required in daily operation. However if draining is to be performed, it must be performed with at least one of the two booster pumps operating to prevent air from being drawn into the system

Turbomeca has developed a design improvement of both the FCU NTL and Ng seals, with a NTL seal replacement in the field by the end of 2011 and a planned introduction date of the Ng seal by the end of 2012.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 03 January 2012.

Appendix A – Clear Tubing, Air in Fuel System

Appendix A. Clear Tubing, Air in Fuel System

Appendix B – Representations made on behalf of Bureau d’Enquêtes et d’Analyses (BEA)

Note: The first paragraphs of this document are available in French only.

Appendix A. Representations made on behalf of Bureau d'Enquêtes et d'Analyses (BEA) - 1 -

Appendix A. Representations made on behalf of Bureau d'Enquêtes et d'Analyses (BEA) - 2 -

Appendix A. Representations made on behalf of Bureau d'Enquêtes et d'Analyses (BEA) - 3 -


  1. 50% fuel capacity equates to approximately 270 litres Jet A–1. ↑
  2. All times are Central Standard Time (Coordinated Universal Time minus 6 hours). ↑
  3. A flameout is a term used to describe when combustion in a gas turbine engine unintentionally stops. ↑
  4. Determined through informal survey of several Canadian helicopter operators. ↑
  5. Ng denotes gas generator and NTL denotes free turbine where N is a speed and TL is free turbine (turbine libre). ↑

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Aviation Reports – 2010 – A10O0089

| Transportation Safety Board Reports | January 26, 2012

Transportation Safety Board of Canada

Aviation Reports – 2010 - A10O0089

The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Risk of Collision
NAV CANADA – Toronto Area Control Centre
Toronto/Billy Bishop Toronto City Airport
Toronto, Ontario, 6 nm SE
11 May 2010

Report Number A10O0089

Synopsis

Porter Airlines Inc. Flight 406, a Bombardier DHC8-402 (registration C-FLQY, serial number 4306) was on an instrument flight rules flight to the Toronto/Billy Bishop Toronto City Airport, Ontario. Southeast of the airport, the flight was cleared for a visual approach to Runway 08. Another Porter Airlines Inc. Flight 249, also a Bombardier DHC8-402 (registration C-GLQX, serial number 4282) was departing Runway 08 on an IFR flight eastbound with a clearance to depart under visual flight rules until 10 minutes after departure. At approximately 0839 Eastern Daylight Time, about 6 nautical miles southeast of the airport, both aircraft responded to resolution advisories from their respective traffic collision-avoidance systems. The aircraft crossed paths separated by approximately 300 feet vertically.

Other Factual Information

Air traffic services (ATS) at the Toronto/Billy Bishop Toronto City Airport (Billy Bishop Airport) are provided by Nav Canada through a control tower located on the airport, and the Toronto Area Control Centre (ACC) located at Toronto/Lester B. Pearson International Airport.

Instrument flight rules (IFR) control services at the ACC are provided by the Airports Specialty and is divided into 3 sectors:

  • East Satellite;
  • West Satellite; and
  • London.

At the time of the occurrence, there were 4 controllers, 1 supervisor and 1 controller in training on duty.

The London sector was only staffed by 1 controller. The East and West satellite sectors were combined and being staffed by the occurrence controller while the supervisor was providing on-the-job instruction to the controller in training. The other 2 controllers were on break but were available for immediate recall.

Sectors may be combined when traffic levels and controller workload are low which can ease workload by reducing coordination between the sectors. However, when traffic increases, combining sectors can result in overlapping air-ground and ground-ground communications. This resulted in less time available for the controller to identify and resolve conflicts. The responsibility to combine or split the sectors is based on actual and anticipated traffic and rests with the supervisor.

The occurrence controller (satellite controller) was occupying the radar position of the combined satellite sectors. The supervisor was providing on-the-job instruction related to the data position. At the time of the occurrence, the satellite controller was engaged in discussions with the controller in training. According to the Unit Operations Manual (UOM), the duties of the data position include, in part, identifying and resolving conflicts and coordinating with the radar controller. 1

At 0834 2 Porter Flight 406 (POE406) was 20 nautical miles (nm) east of the Billy Bishop Airport at 7000 feet above sea level (asl). The satellite controller cleared POE406 for a visual approach to Runway 08. As no request to restrict the descent of IFR arrivals had been received from the Billy Bishop Airport controller (airport controller) as per the Arrangement between ACC and the Toronto City Control Tower (Arrangement), 3 the visual approach clearance authorized POE406 to descend at the flight crew’s discretion, with no restriction.

Meanwhile, Porter Flight 249 (POE249) asked the airport controller for its IFR clearance with a request for a visual flight rules (VFR) departure. Normally, departing IFR aircraft would be issued the Island Eight SID (standard instrument departure). However, weather permitting IFR flights often request clearances to conduct VFR departures to expedite traffic during busy periods. As the weather conditions were suitable, the airport controller issued a clearance in accordance with article D.1.6 of the Attachment to the Arrangement which states: “Maintain VFR for 10 minutes after take-off. Climb not above 2,000 feet.” The airport controller included a heading of 141° which forms part of the Island Eight SID.

Subsection 801.02(3) of the Canadian Aviation Regulations (CARs) states: “Where air traffic services are provided to aircraft operating in Class D airspace (such as the airspace surrounding CYTZ), the services shall include (b) separation between all IFR aircrafts.”  The minimum separation required in this case would be 1000 feet vertically or 3 nm laterally.

With regard to IFR clearances with VFR restrictions, subsection 6.2.1 of the Aeronautical Information Manual (TP14371) reminds pilots of their responsibility to provide their own separation from other IFR aircrafts. It further explains that: “controllers normally issue traffic information concerning other IFR aircrafts” and that “if compliance with the restriction is not possible, the pilot should immediately advise air traffic control (ATC) and request an amended clearance.” In this occurrence, traffic information was not issued.

There is no requirement in the CARs for ATC to provide separation between IFR and VFR aircrafts in Class D airspace. However the ATC Manual of Operations (MANOPS) requires that conflict resolution be provided when equipment and workload permits. Conflict resolution requires either visual separation or a minimum of 500 feet vertically or 1 mile laterally.

As POE249 requested a VFR departure, its flight crew assumed responsibility for separation and reduced the spacing from other IFR aircraft that would be afforded to them by ATC.

At 0835, as per the Arrangement, the satellite controller informed the airport controller that POE406 was 20 nm to the east and cleared for a visual approach for Runway 08. The airport controller acknowledged this information and requested validation of the IFR clearance for POE249. The satellite controller validated the IFR clearance with the instruction to depart VFR.

For the next 2 minutes, the satellite controller became moderately busy, making approximately 15 transmissions pertaining to other aircrafts or units in the combined sectors. During the period leading up to the occurrence, aircraft transmissions sometimes overlapped communications with other ATC facilities.

At 0836, the airport controller cleared POE249 for take-off. In an attempt to ensure there was no conflict with local airport traffic, the airport controller retained POE249 on the tower frequency until it was 3 nm east of the airport climbing through 1900 feet asl. When the airport controller released POE249 to the ACC frequency at 0837, the airport controller did not believe there to be a conflict with POE406 as the airport controller knew the satellite controller was aware of both aircraft.

At this time, POE406 was 10 nm east-southeast of the airport descending through 3300 feet asl. The satellite controller vectored POE406 by instructing it to fly heading 270° to accommodate POE249 departing. Forgetting that a clearance for an unrestricted visual approach had already been issued, the satellite controller informed POE406 that it would receive an approach clearance and frequency change shortly.

At 0837, POE249 attempted to contact the satellite controller advising that it was leveling at 2000 feet asl and in the turn to heading 141°. The satellite controller did not hear this call since he was busy communicating with a different controller regarding an unrelated control issue in the West satellite sector. The satellite controller then called the airport controller seeking communications with POE249.  Sixteen seconds later, communication was established between POE249 and the satellite controller, and POE249 restated its position. Without acknowledging that transmission, the satellite controller immediately instructed POE406 to level off at 2500 feet asl. POE406 reported that it had already descended through 2300 feet asl but would climb back to 2500 feet asl.

Figure 1. Flight Paths
Figure 1. Flight Paths ↑

At 0838, the satellite controller informed POE249 of the position of POE406 situated 1.5 nm away at 2300 feet asl. Six seconds later, POE249 reported the traffic in sight.

For 10 seconds, another aircraft transmitted on the frequency. During this time, both POE249 and POE406 received and responded to their respective traffic collision avoidance system (TCAS) resolution advisories. Seconds later, POE249 and POE406 crossed paths 300 feet vertically apart, 6 nm east southeast of Billy Bishop Airport (see Figure 1).

Controller History

The airport controller had been employed by NAV CANADA since 2006 and was certified and qualified in accordance with existing regulations. The airport controller had worked 5 consecutive days prior to this date as part of his regular schedule, and was considered well rested at the time of the occurrence.

The satellite controller had been employed by NAV CANADA since 2000 and was certified and qualified in accordance with existing regulations. The satellite controller’s previous shift ended the evening before at 2300. Prior to this, the controller was off for 4 days. During this time off, the controller was attending to distressing personal matters that had been on-going since December 2009.  Shortly after these personal matters began, the satellite controller’s sleep quality diminished, and total sleep time was reduced to an average of 6 hours per night.

The satellite controller was not scheduled to work on this day but accepted an overtime shift and started work at 0700, having been called for this shift earlier that morning. At the time of the incident, the satellite controller was not well-rested.

Fatigue and Human Performance

Shortening a person’s sleep time to less than what he or she requires results in fatigue. 4, 5  Studies have also shown that the chronic restriction of sleep from 8 hours to 6 hours per night results in daytime fatigue. Fatigue will impair many facets of human performance. Impairments include reductions in memory and cognitive abilities. 6

A controller’s ability to maintain separation distances between aircraft as well as to predict separation distances from flight paths is dependent upon his or her working memory. Working memory refers to a memory system that temporarily stores information while it is being manipulated for tasks such as the problem solving and reasoning 7 as is required for maintaining and predicting separation between aircraft. It requires the simultaneous storage and processing of information. Working memory can be impaired by fatigue. 8

In addition to working memory, fatigue reduces cognitive abilities such as cognitive processing speed. The speed with which a controller can identify important information, process and react to it is a function of cognitive processing speed. Cognitive processing speed is reduced by fatigue. 9

NAV CANADA Fatigue Management

A risk of fatigue-induced human performance decrements is inherent in all 24-hour operations. To address this risk, NAV CANADA developed a fatigue management program (FMP) which is integrated into its safety management system. The FMP includes a number of components such as controller education, preventative and operational strategies, controller scheduling practices, and the concept of shared responsibility. All operational controllers, including those involved in this occurrence, receive information on fatigue management during their basic and recurrent training.

The goal of the training is to encourage controllers to use operational and preventative strategies to help manage the risk of fatigue and related decrements in human performance. Preventative strategies are used before shifts to properly manage sleep-wake patterns and reduce the likelihood of fatigue. Operational strategies are used during a shift to maintain alertness and performance levels. These strategies include consuming caffeine, taking short physical activity breaks and changing the environmental conditions of the workplace.

One of the preventative strategies included is a questionnaire designed to assess whether or not a person is fatigued (see Appendix A). A set of questions is asked to draw attention to fatigue risk factors such as: personal fatigue signs and symptoms, acute sleep loss, cumulative sleep debt, time of day, circadian effects and hours of continuous wakefulness. If the answer is yes to the presence of any one of the risk factors, then the person may be fatigued. Use of the questionnaire is not mandatory. This questionnaire is briefly introduced during the training on fatigue. No instructions regarding when it should be used and by whom it should be used are provided. No other fatigue assessment is performed by either controllers or NAV CANADA.

In addition to the voluntary use of the questionnaire, the FMP relies on controllers to monitor their own fatigue and performance. The relationship between subjective levels of fatigue (i.e. how a controller feels) and estimates of future performance is complex and not completely understood.10 Research seems to indicate that if a person notices that he or she feels some level of fatigue, he or she may be able to correctly estimate that they will not be able to do their job optimally.11 However, research also shows that if a person is in a stimulating environment 12they may not notice that they are fatigued and may not be able to predict that performance may be impaired.

There is currently no agreed upon, reliable and valid standard for assessing subjective fatigue that correlates well with objective measures of fatigue and risk of accidents. The relationship between subjective fatigue questionnaires and objective measures of fatigue is unclear. Some subjective estimates of fatigue (e.g. Visual Analogue Scale (VAS) and Stanford Sleepiness Scale (SSS)) do not correlate well with objective measures of fatigue (e.g. Multiple Sleep Latency Test (MSLT) and number of lapses during a tap test).13

Analysis

The satellite controller was unable to create and maintain a complete mental image of POE249’s position and predicted flight path with that of the arriving flight path of POE406 in working memory. When validating POE249’s departure, the satellite controller did not remember that POE406 had been cleared for an unrestricted visual approach and, as a result, likely did not anticipate the conflict with POE406. This is supported by the fact that the satellite controller later informed POE406 that it would receive an approach clearance and frequency change shortly.

The vector to POE406 and subsequent reference to company traffic suggests the satellite controller did eventually recognize the potential conflict. However, it took time before the satellite controller understood that the conflict had progressed to the point where action had to be taken. Because of the relative lateness of the communication transfer of POE249 and its proximity to POE406 and other workload, the satellite controller did not have time to issue appropriate avoidance instructions.

The controller was moderately busy working the combined sectors with multiple overlapping transmissions. This likely reduced the opportunity for the satellite controller to recognize the conflict and take earlier action to resolve the conflict.

Fatigue results in working memory and cognitive processing impairments. In complex information systems, such as air traffic control, a reduced cognitive processing speed can cause a delay in realizing that a potentially dangerous situation exists. Impaired working memory can also result in difficulty maintaining a complete mental image of complex situations such as aircraft departures, approaches, flight paths and separation distances. These impairments are consistent with the events observed in this occurrence.

A normal nightly sleep requirement is about 8 hours. The satellite controller had been operating with roughly 6 hours of sleep per night for about 5 months. The satellite controller was chronically sleep-deprived and was, therefore, fatigued at the time of the occurrence. This fatigue likely resulted in the impaired working memory and reduced cognitive processing speed of the satellite controller.

NAV CANADA’s Fatigue Management Program (FMP) relies partly on controllers to monitor their own fatigue and performance. The fatigue questionnaire was voluntary and was not used by the satellite controller. In addition, the stimulation of the work environment likely prevented the controller from noticing his level of fatigue. Therefore, unacceptable levels of fatigue and performance decrements while on duty may not always be identified.

Findings as to Causes and Contributing Factors

  1. The satellite controller did not initially recognize the potential conflict between the POE249’s departure and POE406’s arrival when validating POE249’s departure.
  2. The satellite controller did not remember that an approach clearance without restriction had already been issued to POE406.
  3. The controller was moderately busy working the combined sectors which contributed to the late recognition of the conflict. There was insufficient time to take corrective action, resulting in a risk of collision.
  4. The satellite controller was fatigued, thus resulting in working memory and cognitive processing impairments.

Finding as to Risk

  1. Reliance on controllers monitoring their own level of fatigue may not always effectively identify unacceptable levels of fatigue.

This report concludes the Transportation Safety Board’s investigation into this occurrence. Consequently, the Board authorized the release of this report on 22 December 2011.

Appendix A —NAV CANADA Fatigue Questionnaire

When you become fatigued, you lose the ability to judge your own level of alertness. Typically, you overestimate your level of alertness when fatigued. Despite this decreasing accuracy as you become fatigued, you can teach yourself to better recognize your personal signs of fatigue and to recognize personal factors in yourself and others. Use the following checklist to help you better assess your current level of alertness and fatigue.

PERSONAL FATIGUE SIGNS & SYMPTOMS Yes  No  
  (Write in your personal fatigue signs and symptoms below)    
1. Example: My eyes are red and itchy    
2.      
3.      
4.      
5.      
PERSONAL FACTORS    
Acute Sleep Loss    
6. Have you gotten 2 hours less sleep than your body requires in the last 24-hours? (For example, if you need 8 hours of sleep each 24-hours, did you get less than 6 last night?)    
Cumulative Sleep Debt    
7. Have you been unable to get 2 consecutive nights of at least 8 hours of sleep in the past 5 days?    
Time of Day/Circadian Effects    
8. Are you in a period of internal body clock / circadian low between 3-5 am or 3-5 pm?    
Hours of Continuous Wakefulness    
9. Have you been awake for longer than 16  hours?    

If you answered “No” to all of the questions above, you are probably well rested. The more questions to which you answered “Yes”, the less likely you are to be well rested. A “Yes” answer to any of the question above is an indication that you may be fatigued.


  1. Unit Operations Manual ES 1.5 – Duties of West Satellite Data Position. ↑
  2. All times Eastern Daylight Time (Coordinated Universal Time minus 4 hours). ↑
  3. Article D.2.10 of the Arrangement states: “The Toronto ACC shall, when requested by the control tower, apply a descent restriction to aircraft cleared for a visual approach in accordance with Attachment A, unless otherwise coordinated.” Attachment A stipulates: “Not below 3000’ until advised by the tower.” ↑
  4. A. M. Anch, et al., Sleep: A Scientific Perspective, New Jersey: Prentice-Hall, 1988. ↑
  5. Tucker, P., Smith, L., MacDonald, I., & Folkard, S.,”Shift length as a determinant of retrospective on-shift alertness”,  Scandinavian Journal of Work, Environment and Health, 1998, 24(Suppl. 3), 49-54. ↑
  6. See for examples:
    1. Dinges, D., Pack, F., Williams, K., Gillen, K., Powell, J., Ott, G., Aptowicz, C., and Pack, A. (1997) “Cumulative sleepiness, mood, disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night” Sleep, 20(4), pp. 267-277.
    2. Ingre, M., Åkerstedt, T., Peters, B., Anund, A. & Kecklund, G. (2006). “Subjective sleepiness, simulated driving performance and blink duration: Examining individual differences”, Journal of Sleep Research, 15, pp. 47-53 ↑
  7. Baddeley, A. (1992).  “Working memory”,  Science, 255(5044). pp. 556-559. ↑
  8. See for examples:
    1.  Dinges, D. (1992), “Probing the limits of functional capability:  The effects of sleep loss on short –duration tasks”, In Broughton, R. (Ed.) Sleep, Arousal, and Performance. Boston: Birkhäuser, pp. 177-188.
    2. Galy, E., Mélan, C., & Cariou, M. (2008). Investigation of task performance variations according to task requirements and alertness across the 24-h day in shift workers. Ergonomics, 51(9), pp. 1338-1351. ↑
  9. See previous note. ↑
  10. Rogers, N., & Dinges, D. (2003).  Subjective surrogates of performance during night work. Sleep, 26,  pp. 790-791. ↑
  11. Dorrian, J., Lamond, N., & Dawson, D.  (2000). The ability to self-monitor performance when fatigued. Journal of Sleep Research, 9, pp. 137-144. ↑
  12. Yang, C., Lin, F., & Spielman, A. (2004).  A standard procedure enhances the correlation between subjective and objective measures of sleepiness.  Sleep, 27, pp. 329-332.
    Dinges, D. & Graeber, R. (1989).  Crew fatigue monitoring. Flight Safety Foundation: Flight Safety Digest, October, 65-75. ↑
  13. Johnson, L., Freeman, C., Spinweber, C., & Gomez, S. (1988). The relationship between subjective and objective measures of sleepiness. Report No. 88-50, Naval Health Research Center: San Diego, CA. ↑

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