TSB Final Report Summaries

The following summaries are extracted from final reports issued by the Transportation Safety Board of Canada (TSB). They have been de-identified and include the TSB’s synopsis and selected findings. Some excerpts from the analysis section may be included, where needed, to better understand the findings. For the benefit of our readers, all the occurrence titles below are now hyperlinked to the full TSB report on the TSB Web site. —Ed.

TSB Final Report A10W0040—Runway Incursion

On March 2, 2010, Calgary International Airport was operating under its reduced visibility operations plan (RVOP) with Runway 16 as the only active runway. The runway visual range (RVR) for Runway 16 was variable, from 1 400 to 4 000 ft, for most of the morning. There were 12 aircraft lined up for departure from the threshold, two from Taxiway C4 and one from Taxiway U at mid field. After a BAE 125-800A commenced its takeoff roll from the threshold, a de Havilland Dash 8 was instructed to line up and wait at the threshold of Runway 16. The Dash 8 was the aircraft at Taxiway U. At 09:45 MST, after the Dash 8 crew queried the instruction, the airport controller confirmed it and advised the Dash 8 crew to be ready for an immediate takeoff. The Dash 8 crossed the hold line at Taxiway U as the BAE-125 passed overhead, climbing to 400 ft AGL. The TSB authorized the release of this report on October 21, 2010.


Airport Surface Detection Equipment (ASDE) display at 0943:49

Analysis

Pilot and Controller Communication

As a result of the long delay between arrival at Taxiway U and issuance of the takeoff clearance, the airport controller lost track of the location of the Dash 8 and did not use the Extended Computer Display System (EXCDS)Footnote 1 to support or contradict the airport controller's mental model.

The controller believed the Dash 8 to be at the threshold of Runway 16 (Taxiway C8), and the flight crew believed the controller knew they were at Taxiway U. It is likely that, as a result of the unexpected clearance of two flights between arriving flights, the flight crew of the Dash 8 felt rushed to get into position and simultaneously unsettled by their takeoff clearance that appeared to be sequenced much more quickly than previous departures. The assimilation of the departure heading instruction, the completion of the before takeoff check list, and the concern about a possible aircraft departing from the threshold all contributed to a high workload for the flight crew of the Dash 8. This would have resulted in little reserve to figure out that ATC believed them to be at Taxiway C8, as opposed to Taxiway U. Similarly, the airport controller did not have enough verbal information from the flight crew's query to alter his assumption of the Dash 8’s position before reiterating the instruction to line up.

The Canadian Aviation Regulations (CARs) do not require flight crews to read back the location for line up or takeoff instructions. During times of restricted visibility, when an aircraft cannot be positively identified visually, the primary tool for a controller to identify it and its location is through pilot and controller communications. To ensure that the information is received by the pilot and understood, a read back and hear back must be done.

Calgary Tower Staffing Levels

During the day, the normal complement in the tower was six controllers plus a supervisor. Due to the absence of two controllers, there was insufficient staff to cover all five controlling positions and allow for breaks. As a result, the supervisor took a controlling position, while the tower coordinator position was left vacant. Due to the complexity of the situation and the volume of traffic waiting for departure, this was done in favour of opening the second ground position.

Seeing as the tower coordinator position was vacant, there was one less opportunity to correct the airport controller's misconception regarding the position of the Dash 8.

ASDE and RIMCAS

The airport surface detection equipment (ASDE) installed at Calgary International Airport worked as designed. Due to reduced visibility on the day of the occurrence, the ASDE display was the primary source of information for controlling aircraft that were on the manoeuvring areas. However, the Calgary ASDE does not have aircraft identification tags to differentiate one target from another. Consequently, the controller's ability to acquire and maintain an accurate picture of the departure situation was impeded.

The controller formulated a mental picture as to the position of the next five departing aircraft, based on incomplete information provided on the ASDE display and the flight data entries on the EXCDS display. Although the Dash 8 was identified at Taxiway U on the EXCDS display, the information presented was not used by the controller to either support or contradict the controller's mental model. At the time of the occurrence, the controller's attention was directed towards the ASDE display while waiting for movement of the targeted flight to confirm that the flight was making appropriate and timely movement towards its takeoff position. The ASDE target's lack of movement at the threshold of Runway 16 ultimately triggered the controller to identify the true location of the aircraft at Taxiway U.

The runway incursion monitoring and collision avoidance system (RIMCAS) was disabled due to nuisance alarms associated with the configuration of multiple intersecting runways at Calgary International Airport. However, when the reduced visibility operations plan (RVOP) was active, only one runway was allowed for arrivals and departures. There was a missed opportunity for RIMCAS to be configured for single runway operations in order to provide another layer of defence against collisions in low visibility conditions.

RVOP

Intersection takeoffs were being allowed to facilitate the movement of aircraft from the apron to Runway 16, given its close proximity to the threshold of Runway 16. The Calgary International Airport RVOP allowed for such operations when the ASDE was working. However, ASDE provides limited protection against incursions and, with RIMCAS disabled, there was limited protection against collisions.

Runway Incursion Prevention Initiatives

Given the risk posed to Canadians by runway incursions, as emphasized by the Transportation Safety Board in its 2010 Watchlist, this report again highlights the pressing need for improvement while acknowledging the progress that has been made to date.

Findings as to causes and contributing factors

  1. As a result of the long delay between arrival at Taxiway U and the issuance of the takeoff clearance, the airport controller lost track of the location of the Dash 8 and did not use the information presented on the EXCDS to either support or contradict the airport controller's mental model.

  2. In its communications with the tower, the Dash 8 flight crew did not hear the controller's instruction to line up at the threshold and did not include their location information, resulting in the airport controller maintaining the perception that the Dash 8 was at the threshold.

  3. The tower was operating at reduced staffing levels, with the tower coordinator position vacant, resulting in one less opportunity to correct the controller's perception of where the Dash 8 was on the field.

  4. The ASDE display does not show the identification tags of departing aircraft, allowing the controller to continue with the mistaken belief that the Dash 8 was at the threshold rather than at Taxiway U.

  5. The RIMCAS feature was not enabled, thus removing an opportunity for the controller to be alerted to the Dash 8 crossing the hold line while the BAE-125 was becoming airborne.

  6. The RVOP allowed for multiple intersection takeoffs with ASDE, a less than adequate defence, to mitigate the risk of runway incursions.

Finding as to risk

  1. Seeing that the CARs do not require flight crews to read back their location when acknowledging instructions to enter an active runway, there is a risk of runway incursions, as controllers are unable to confirm aircraft position and flight crew understanding of the instruction.

Safety Action Taken

NAV CANADA

On March 3, 2010, Operations Letter 10-004 was issued by the NAV CANADA site manager for the Calgary tower. The letter stated, in part, that the following procedures would be implemented immediately:

"While RVOP is in effect, no aircraft shall depart from any intersection along a runway unless the tower coordinator position is opened and manned."

In addition, the tower operations committee has been tasked with reviewing the use of intersection departures during RVOP.

On October 9, 2010, Operations Letter 10-015 was issued by the NAV CANADA site manager for the Calgary tower to replace Operations Letter 10-004. The letter advised that the operations committee had reviewed the use of intersection departures during RVOP and had agreed to discontinue the practice unless the tower coordinator position was manned. This directive is now permanent.

The virtual stop bar feature in the ASDE system at the Calgary control tower is being put into use for reduced visibility operations. Software updates, system testing and controller training are to be completed by mid-November 2010.

Furthermore, NAV CANADA coordinates the Runway Safety and Incursion Prevention Panel (RSIPP), a national interdisciplinary forum which monitors and addresses runway safety issues. The mandate of the panel is to promote runway safety and reduce safety risks, particularly runway incursion risks. (For more , visit www.navcanada.ca and click on RUNWAY SAFETY.)

Dash 8 Operator

The operator of the Dash 8 issued a flight operations bulletin for its operations conducted under subparts 703, 704 and 705 of the CARs stating that effective immediately, they would apply full length departures from all runways when the low visibility operations plan (LVOP) or RVOP are in effect.

Additionally, the following was incorporated into their operations manual:

“Communicating with Tower/Radio: When holding short, regardless of frequency congestion or position, crew will state their position on the field (for example, "[call sign] holding short Runway 16 on Uniform"). This includes hand over to Tower from ground frequency. This ensures flight crew and ATC are working together to keep situational awareness.”

Footnotes

Footnote 1

EXCDS is an advanced tower, terminal, airport and en route coordination system that permits controllers to manage electronic flight data online, using touch sensitive display screens. EXCDS automates flight data transactions thereby eliminating the need for paper handling, reducing voice communications and minimizing head down time. EXCDS will also display current airport conditions (such as wind, altimeter, RVR, runway light brightness and active runways). Use of EXCDS at Calgary has resulted in a nearly paper-free environment, where paper strips are used as a backup only and most coordination tasks are automated. The EXCDS also gathers data for billing and statistical purposes. An EXCDS flight strip can track more than 110 different data items (such as time of departure, aircraft type, destination, and parking gate).

Return to footnote 1 referrer

TSB Final Report A10C0060—Fuel Starvation and Forced Landing

On May 13, 2010, a Beech 95-55 departed Thicket Portage for a day VFR flight to Thompson, Man., about 29 NM north. Shortly after takeoff, the pilot used his cell phone to contact the Winnipeg flight information centre (FIC). The pilot indicated that the aircraft was experiencing an electrical problem and that the flight would arrive at Thompson in 12 min, without radios or transponder. There were no further communications with the aircraft. About 30 min after the telephone call was received, a series of emergency signals from a tracking system carried by the pilot were received. A helicopter was dispatched to the location indicated by the tracking system. The aircraft was located about 3 NM east of Pikwitonei, about 25 NM northeast of Thicket Portage and 27 NM southeast of Thompson. The pilot, the sole occupant, sustained minor injuries. The aircraft was destroyed on impact with trees and terrain, but the emergency locator transmitter (ELT) did not activate. There was no post-crash fire. The accident occurred during daylight hours at about 09:50 CDT. The TSB authorized the release of this report on February 16, 2011.

Analysis

The first indication of a loss of electrical power occurred immediately after take-off, when the electrically-operated landing gear did not fully retract and all avionics power was lost. The transponder also stopped transmitting and the aircraft was no longer being tracked by radar.

The simultaneous occurrence of these electrical malfunctions indicates that they are likely related to low electrical bus voltage caused by a loss of both generators, combined with low battery voltage.

The pilot's response to the electrical malfunction after take off was to communicate rather than aviate first and assess the malfunction and then navigate. The cell phone call to the FIC distracted the pilot from assessing the extent of the electrical problem and taking corrective action in a systematic way. Because the air-driven directional gyro (DG) had not been set and a ground feature had not been selected prior to take off to confirm the departure track, the pilot's VFR navigation technique relied solely on the heading reference provided by the electrically-powered horizontal situation indicator (HSI). The HSI malfunction due to the electrical problem was not immediately recognized and consequently, the pilot became lost. When smoke or fumes were detected in the cockpit the pilot had lost situational awareness. This loss of situational awareness eliminated the pilot's best option, which was an immediate return to Thicket Portage, while completing the aircraft checklist for electrical smoke or fire.

The pilot was uncertain of his exact position, he was dealing with an electrical power failure and a landing gear malfunction as well as the possibility of a fire. The pilot actions indicate that task saturation had occurred. With the exception of using the standby magnetic compass to confirm the orientation of the railroad tracks, the pilot did not prioritize the critical actions required. Fuel management was not addressed and the auxiliary tanks were not selected in cruise. The pilot's attention became focused on the landing gear malfunction which was dealt with prior to completing the items listed in the electrical fire or smoke emergency checklist. These items were not completed for some 15 minutes as indicated by the appearance of the aircraft's transponder target on radar in the vicinity of Pikwitonei. The landing gear remained a priority and the pilot extended the approach path and rocked the aircraft to ensure the gear was locked down.  The pilot concentrated on this activity and did not address the fuel state of the aircraft.

Area map showing the aircraft track up to accident site.

The engines stopped shortly after the aircraft was rocked to lock the landing gear. The loss of fuel supply and the stoppage of the right engine were likely due to fuel exhaustion as the fuel in the right main tank became depleted. The left engine stopped almost immediately after the right engine had stopped. The stoppage of the left engine may also have resulted from fuel exhaustion if the engines had burned an equal amount of fuel since the aircraft had last been fueled. It is more likely, however, that the engine stopped as a result of fuel starvation as the low level of fuel in the tank allowed the port to become uncovered when the aircraft experienced yaw from asymmetric thrust. The decision not to feather the propeller on the right engine would have resulted in increased drag and greater yaw forces, causing the fuel to move away from the fuel port at the inboard edge of the left tank. With the gear already down, the pilot's decision not to feather either propeller increased the rate of descent and reduced the pilot's ability to control the forced landing.

Findings as to causes and contributing factors

  1. The electrical system likely failed due to low electrical bus voltage caused by the failure of the right voltage regulator and low voltage output of the left regulator.

  2. The pilot became distracted while communicating with the FIC by cell phone and did not prioritize the handling of the electrical failure and navigation. Consequently, the pilot became lost.

  3. Task saturation, due to the pilot's low experience and currency level, limited the pilot's ability to respond effectively to the multi-faceted emergency. Consequently, the fuel situation was not addressed and the engines stopped because of fuel starvation and fuel porting.

Findings as to risk

  1. The pilot did not activate the SPOT Track Progress mode and the ELT did not activate during the crash despite the severity of the impact with the terrain. As a result, the pilot's rescue could have been delayed.

  2. The fuel quantity indicator gauges were not marked with a yellow band as required by regulation. The absence of the yellow band increased the risk of takeoff in this prohibited range by removing a visual warning of low fuel condition.

  3. The aircraft's single-axis G-switch ELT, though approved and serviceable, did not activate during the crash despite the severity of the impact with the terrain. As a result, the pilot's rescue could have been delayed.

Other finding

  1. Serious injuries were prevented by the use of a lap belt with shoulder harness.

TSB Final Report A10Q0098—Engine Problem—Collision with Terrain

Note: The TSB investigation into this occurrence resulted in a major report, with extensive discussion and analysis on many issues such asnormal, abnormal and emergency procedures, pilot training, company management, oversight, surveillance and more. Therefore we could only publish the summary, findings and safety action in the ASL. Readers are invited to read the full report, hyperlinked in the title above. —Ed.

On June 23, 2010, a Beechcraft A100 King Air was making an IFR flight from Québec to Sept-Îles, Que. At 05:57 EDT, the crew started its takeoff run on Runway 30 at Québec/Jean Lesage International Airport. Just over a minute later (68 s), the co-pilot informed the airport controller that there was a problem with the right engine and that they would be returning to land on Runway 30. Shortly thereafter, the co-pilot requested aircraft rescue and fire fighting (ARFF) services and informed the tower that the aircraft could no longer climb. A few seconds later, the aircraft struck the ground 1.5 NM from the end of Runway 30. The aircraft continued its travel for 115 ft before striking a berm. The aircraft broke up and caught fire, coming to rest on its back 58 ft further on. Two crew members and five passengers died in the accident. No signal was received from the emergency locator transmitter (ELT). The TSB authorized the release of this report on July 4, 2012.


Illustration of impact sequence 

The aircraft struck the ground approximately 1.5 NM past the end of Runway 30, 900 ft to the right of the extended centreline. Initial impact was made in a direction of approximately 320° magnetic, banking right. The right wingtip left a 5-ft long furrow in the ground 173 ft before the wreckage. The marks made by the left wing in a tree (BΔ) show that the aircraft was banking right at approximately 23°.
                                          
About 92 ft further, there were marks made by the left propeller (C). The space between the first three marks made by the propeller is 0.8 ft. Analysis of these marks revealed that the aircraft was travelling at 69.7 kt, based on the assumption that the engine rpm was 2 200 at that specific time. Approximately 23 ft further on, the left wing hit a berm (D), causing the fuselage to roll to the right. The right wing broke on the ground, the right engine (G) separated from the wing and the fuel tank was crushed. After point (C), where the left propeller struck the ground, the aircraft travelled just over 82 ft before coming to rest on its back (F). Much of the aircraft was destroyed by fire. The fire may have been caused by electrical arcing resulting from damaged electrical harnesses, the heat of the engines and possibly by friction from the sheet metal coming into contact with the fuel.

Findings as to causes and contributing factors

  1. After takeoff at reduced power, the aircraft performance during the initial climb was lower than that established at certification.

  2. The right engine experienced a problem in flight that led to a substantial loss of thrust.

  3. The right propeller was not feathered; therefore, the rate of climb was compromised by excessive drag.

  4. The absence of written directives specifying which pilot was to perform which tasks may have led to errors in execution, omissions and confusion in the cockpit.

  5. Although the crew had the training required by regulation, they were not prepared to manage the emergency in a coordinated, effective manner.

  6. The priority given to ATC communications indicates that the crew did not fully understand the situation and were not coordinating their tasks effectively.

  7. The impact with the berm caused worse damage to the aircraft.

  8. The aircraft's upside-down position and the damage it sustained prevented the occupants from evacuating, causing them to succumb to the smoke and the rapid, intense fire.

  9. The poor safety culture at the operator contributed to the acceptance of unsafe practices.

  10. The significant measures taken by TC did not have the expected result of ensuring compliance with the regulations and consequently, unsafe practices persisted.

Findings as to risk

  1. Deactivating the flight low pitch stop system warning light or any other warning system contravenes the regulations and poses significant risks to flight safety.

  2. The maintenance procedures and operating practices did not permit the determination of whether the engines could produce the maximum power of 1 628 ft-lb required at takeoff and during emergency procedures, thereby posing major risks to flight safety.

  3. Besides being a breach of regulations, a lack of rigour in documenting maintenance work makes it impossible to determine the exact condition of the aircraft and poses major risks to flight safety.

  4. The non-compliant practice of not recording all defects in the aircraft journey log poses a safety risk because crews are unable to determine the actual condition of the aircraft at all times and, as a result, could be deprived of information that may be critical in an emergency.

  5. The lack of an in-depth review by TC of standard operating procedures (SOPs) and checklists of 703 operators poses a safety risk because deviations from aircraft manuals are not detected.

  6. Conditions of employment, such as flight hr-based remuneration, can influence pilots' decisions and create a safety risk.

  7. The absence of an effective, non-punitive and confidential voluntary reporting system means that hazards in the transportation system may not be identified.

  8. The lack of recorded information significantly impedes the TSB's ability to investigate accidents in a timely manner, which may prevent or delay the identification and communication of safety deficiencies intended to advance transportation safety.

Safety action taken

Transport Canada

Transport Canada has made significant changes to its surveillance program. These changes include updates to the methods used for surveillance planning and the introduction of tools that provide an improved capacity for the monitoring and analysis of risk indicators within the aviation system.

TSB Final Report A10O0145—Collision with Tower

On July 23, 2010, at 12:26 EDT, a commercially registered Bell 206B departed North Bay for a VFR flight to Kapuskasing, Ont. The pilot was repositioning the helicopter for sightseeing flights planned at a local festival the next day. Another company pilot was a passenger. During the flight, poor weather conditions were encountered and approximately 1 hr and 12 min after departure, in the vicinity of Elk Lake, the helicopter collided with a tower approximately 79 ft in height. The helicopter then struck the ground approximately 430 ft beyond the tower and was destroyed. Both occupants were fatally injured; there was no post-impact fire. The emergency locator transmitter (ELT) functioned, but its range was reduced significantly as its antenna was sheared on impact. The TSB authorized the release of this report on November 16, 2011.

Analysis

The pilot called the London flight information centre (FIC) and obtained the weather conditions for North Bay, Timmins and Kapuskasing, all of which reported VFR weather conditions. However, the pilot did not obtain any weather reports or forecast from other stations located near the flight path, such as Sudbury and Earlton, which reported worse weather. Nor did he request a graphic area forecast (GFA) or a pilot weather briefing, both of which would have given the pilot more detailed information about the weather conditions along the flight route. Therefore, he was not fully aware of the weather conditions and consequently briefed senior company personnel that the weather was suitable for the flight.

The flight service specialist did not offer a pilot briefing, which is required by the Flight Services Manual of Operations (FS MANOPS). Had the pilot received all of the available weather information, it might have affected his decision to depart.

All of the METARs were reporting conditions above the minimum required for VFR flight in uncontrolled airspace. However, the elevation at the occurrence site is higher than all of the stations reporting the METARs. Consequently, if the cloud base at the occurrence location was at a similar height to that of the reporting stations, the cloud base above ground would have been reduced. This was confirmed by the actual weather conditions at the occurrence site at the time. There was no data to indicate that this was considered a factor during the flight planning stage.

The helicopter was travelling at a normal cruise speed (104 kt) about 1 000 ft from the tower, and the damage sustained by both the helicopter and tower were indicative of a frontal impact with significant velocity. The global positioning system (GPS) data did not indicate any sudden manoeuvring. The velocity and course appeared constant, implying the pilot did not see the tower with enough time to react prior to impact, likely because the tower was obscured by the weather or blended into the overcast conditions.


Side-by-side photos of the tower pre-and post-impact

About 17 NM prior to the occurrence location, the pilot had deviated from the intended flight path and reduced the helicopter's speed, likely due to higher terrain and weather conditions. However, shortly afterwards, cruise speed was reattained, which decreased the time the pilot had to react prior to tower impact.

The pilot was likely navigating using the VFR navigation chart (VNC) or GPS. However, because the tower was not depicted on the VNC or GPS, the pilot was likely unaware that it existed. The visibility was reduced. The tower was grey coloured, not marked or lit, and may have blended into the overcast conditions, making it difficult to notice. Had the tower been marked on the VNC, the pilot might have noticed the tower depiction in time to deviate or take other corrective action.

The GPS database was not updated. As a result, there was a risk that known depicted obstructions would not have been displayed.

The VNC does not depict small obstacles such as the occurrence tower. The tower did not meet the height requirements to be lighted and marked, or meet the 300 ft mark to be deemed a significant hazard. VNC depict the maximum elevation figure (MEF) to provide information to pilots so that they can avoid terrain and obstacles. Pilots who fly below the MEF and close to the ground are at risk of encountering uncharted obstacles.

Findings as to causes and contributing factors

  1. The pilot did not adequately review the weather for the intended route prior to departure from North Bay. In addition, the flight service specialist did not offer a weather briefing as per the MANOPS. As a result, the pilot was not aware that poor or deteriorating weather conditions existed.

  2. Due to the deteriorating weather conditions, the pilot flew the helicopter at a low altitude. Reduced visibility likely obscured the tower and reduced the available reaction time the pilot had to avoid the tower.

  3. Because the tower was not depicted on the VNC or GPS, the pilot was likely unaware that it existed.

Findings as to risk

  1. The GPS database was not updated. As a result, there was a risk that known depicted obstructions would not have been displayed.

  2. Pilots who fly below the MEF and close to the ground are at risk of encountering uncharted obstacles.

Safety action taken

NAV CANADA

On August 25, 2011, NAV CANADA published an Aeronautical Information Circular (AIC) entitled “VNC Charts - Clarification of the Maximum Elevation Figure”. The AIC contains the following text:

“The MEF is depicted in thousands and hundreds of feet above sea level. The MEF represents the highest feature in each quadrangle. Flight at or below the MEF may be at or below the highest obstruction in that quadrangle. Pilots need to provide a margin for ground and obstacle clearance and for altimeter error. Please see AIM RAC 5.4 602.15 2b (NOTE) and AIM AIR 1.5 for detail. The MEF is calculated based on terrain data and known and unknown obstacles.”

In addition, the AIC describes how the MEF is calculated and states the equation used to complete the calculation.

TSB Final Report A10P0242—Loss of Engine Power and Landing Rollover

On July 29, 2010, a Bell 214B-1 helicopter with two pilots on board, was engaged in firefighting operations approximately 20 NM northwest of Lillooet, B. C. At 11:24 PDT, after refilling the water bucket, the helicopter was on approach to its target near a creek valley. As the helicopter slowed and started to descend past a ridgeline into the creek valley, the engine lost power. The pilot-in-command, seated in the left-hand seat, immediately turned the helicopter left to climb back over the ridgeline to get to a clearing, released the water bucket and the 130-foot long-line from the belly hook, and descended toward an open area to land. The helicopter touched down hard on uneven, sloping terrain and pitched over the nose. When the advancing main rotor blade contacted the ground, the airframe was in a near-vertical, nose-down attitude, which then rotated the fuselage, causing it to land on the left side. A small post-crash fire ignited. The pilot-in-command sustained a concussion and was rendered unconscious. The co-pilot escaped with minor injuries and dragged the pilot-in-command from the wreckage. The pilot-in-command regained consciousness a few minutes later. The helicopter was substantially damaged. The 406 MHz emergency locator transmitter (ELT) activated, but its antenna fitting was fractured; as a result, the search and rescue satellite network did not receive a signal. The TSB authorized the release of this report on April 17, 2013.

Analysis

The occurrence helicopter experienced a loss of power at a critical phase of flight while the pilot was preparing to drop a load of water. In response to the power loss, the pilots identified a nearby landing area and carried out an emergency landing. However, the nature and slope of the terrain in the touchdown area caused the helicopter to roll over after touchdown. The combination of low airspeed, high-density altitude (approximately 9 000 ft), height above ground at the time of the power loss, gross weight of the helicopter, and nature and slope of the terrain precluded an uneventful landing.

Findings as to causes and contributing factors

  1. The engine fuel control unit (FCU) was contaminated with metallic debris that likely disrupted fuel flow and caused the engine to lose power.

  2. The nature and slope of the terrain in the touchdown area caused the helicopter to roll over during the emergency landing.

Findings as to risk

  1. In circumstances where contact between parts results in relative and mutual movement, there is a risk that this can cause wear, generate debris and ultimately result in fractures.

  2. If overhaul procedures and documentation are not clear and detailed, there is increased risk that an impending failure of a component or one of its subcomponents will go undetected and the component or sub-component will be returned to service.

  3. If recurring component failures are not tracked and monitored, there is increased risk that problems associated with the reliability of components will go undetected.

  4. Special Bulletin JFC31 No. 3012 was not incorporated completely, and this bulletin applies to several other aircraft types. Without thorough application of the bulletin, other aircraft are at risk for similar fractures.

  5. If the available shoulder restraints are not worn, there is increased risk of injury during an accident.

Other findings

  1. The FCU was designated as a -22 configuration with a time between overhaul of 2 400 hours; however, it did not have the required modifications. Sixteen additional FCUs were similarly misidentified.

  2. Transport Canada provides the regulatory framework to original equipment manufacturers for the development of instructions for continued airworthiness but does not define the level of overhaul instruction. In this occurrence, the manufacturer's instructions for continued airworthiness were interpreted to allow for overhaul without complete disassembly of subcomponent parts of the FCU.

  3. Both pilots were wearing helmets. The pilot-in-command suffered head and neck injuries during the impact and subsequent rollover.

  4. The investigation could not establish whether wear of the components of the FCU contributed to the power loss and drooping issues reported on this model of FCU, or whether the power loss and drooping issues were related to sending these FCUs for repair before the expected time between overhauls.

  5. Company pilots regularly disabled the engine's overspeed protection system in the Bell 214-B1 model helicopter, and by doing so, removed an engine protection system.

TSB Final Report A10C0159—Engine Shut-down and Forced Landing

On September 10, 2010, a privately registered Piper PA 31-310 Navajo was on a VFR flight from Pickle Lake to Kashechewan, Ont., with a pilot and three passengers on board. Shortly after reaching cruise altitude, there was a brief rumble from the left engine, accompanied by decreases in exhaust and cylinder head temperatures. Consequently, the pilot reversed course. While en route to Pickle Lake, left engine performance deteriorated and the pilot shut the engine down. Unable to maintain altitude, the pilot made a forced landing about 30 NM east of Pickle Lake at 12:15 CDT. The pilot and one passenger sustained minor injuries. The aircraft sustained substantial damage, but there was no post-crash fire. The emergency locator transmitter (ELT) activated on impact. The TSB authorized the release of this report on July 4, 2011.

Photo of wreckage showing the left engine.

Analysis

The initiating event of the occurrence was a magneto failure in the left engine. This failure was the result of the loss of retention of the bushing in the distributor block of the left magneto. The subsequent misalignment of the distributor rotor caused the rotor to fall out of synchronization with the engine. This caused the left engine to run rough, backfire and lose power. The clean, shot-blasted appearance of the piston crowns indicates that the rough running and back firing likely released combustion products that contaminated spark plugs of both magneto systems. It could not be determined whether the engine would have been capable of producing significant power running on the right magneto alone.

The aircraft should have been able to sustain level cruising flight with a single engine. This analysis will consider why the aircraft was unable to do so.

The pilot had not received emergency procedures training on the Navajo and was unfamiliar with its handling characteristics while one engine was inoperative. This unfamiliarity may explain why the pilot did not increase the power on the right engine to maximum when the left engine was shut down. The airspeed decreased incrementally, requiring a corresponding increase in rudder to maintain directional control, which in turn, increased drag. The airspeed continued to decrease and subsequent power increases on the operating engine were insufficient to maintain altitude. The aircraft became difficult to control as it entered the turbulent air and altitude was gradually lost. Eventually, the pilot was required to execute a forced landing.

The Navajo Pilot’s Operating Handbook (POH), Section 3, Engine Inoperative Procedures, does not contain a precautionary engine shutdown procedure. Unlike the Engine Securing Procedure (Feathering Procedure), other engine inoperative procedures in Section 3 contain specific guidance with respect to engine power settings. Consequently, pilots using only this procedure to perform a precautionary shutdown may not apply sufficient power to the operating engine to sustain level flight. The Navajo emergency procedures that pertain to engine failures require the pilot to be practiced and familiar with the procedures for them to be used effectively in a single engine situation.

The aircraft magnetos had been inspected every 100 hr, as required by Piper Navajo service manual checklists. These inspections are sufficient to satisfy the routine maintenance that is required as the magneto accumulates hours in service. However, the inspections were not sufficient to detect an incipient failure that had developed over many hours of operation. If the SB 643B 500-hr inspection recommendations had been completed by following the procedures contained in the Service Support Manual, there would have been several opportunities to detect and correct any distributor block bushing looseness before the magneto failed.

Photo of wreckage seen from the right side, behind the wing.

Findings as to causes and contributing factors

  1. The left magneto distributor rotor gear teeth uncoupled from the input pinion gear, placing the distributor rotor out of time with the engine. As a result, the left engine began to run rough, backfire and lose power.

  2. The pilot shut down the left engine, but did not immediately adjust the power on the operating engine. Airspeed then decreased to a point where the addition of power resulted in the aircraft becoming difficult to control in turbulent conditions.

  3. The gradual loss of altitude eventually required a forced landing.

Findings as to risk

  1. If the Navajo POH, Section 3, Engine Inoperative Procedures, Engine Securing Procedure (Feathering Procedure) is used as a stand-alone procedure, there is a risk that sufficient power may not be applied to the operative engine to maintain flight.

  2. If the 500-hr magneto inspection recommendation of Service Bulletin 643B is not followed, there is a risk that the looseness of the distributor block bushing will go undetected and uncorrected.

TSB Final Report A10C0214—Engine Power Loss and Autorotative Landing

On December 12, 2010, during daylight hours, a Eurocopter AS 350 B2 helicopter was conducting slinging operations approximately 6 NM northeast of Pickle Lake Airport, Ont. 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 ft AGL, 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 (ELT) did not activate. The accident occurred at 08:00 CST. The TSB authorized the release of this report on January 3, 2012.

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 a leaking fuel control unit (FCU) NTL or NgFootnote 2 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 hr 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 Rotorcraft Flight Manual (RFM) and the Aircraft Maintenance Manual (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.

Safety action taken

Due to similarities between this occurrence and a 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).

On July 26, 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.

Footnotes

Footnote 2

Ng denotes gas generator and NTL denotes free turbine where N is a speed and TL is free turbine (turbine libre).

Return to footnote 2 referrer

TSB Final Report A11A0035—Runway Overrun

On July 16, 2011, at 06:45 NDT, a Boeing 727-281 departed Moncton International Airport, N.B., for St. John’s International Airport, N.L., on a scheduled cargo flight with three crew members on board. An instrument landing system (ILS) approach was carried out and at 08:09 NDT the aircraft touched down on Runway 11. Following touchdown, the crew was unable to stop the aircraft before the end of the runway. The aircraft came to rest in the grass, with the nose wheel approximately 350 ft beyond the end of the pavement. There were no injuries and the aircraft had minor damage. The TSB authorized the release of this report on January 23, 2013.

Analysis

Hydroplaning

The aircraft touched down about 1 850 ft from the threshold and at a higher than required airspeed, which reduced the available runway length to stop the aircraft.

About 8 seconds after touchdown, the crew applied the wheel brakes and almost immediately noted that the aircraft was skidding. Braking was maintained throughout the landing roll and up until the aircraft stopped. Pieces of reverted rubber were found on the runway near the touchdown point and along the left side of the runway up to where the aircraft departed the pavement. This indicates the aircraft experienced reverted rubber hydroplaning almost immediately after the brakes were applied and periodically throughout the landing roll.

Should skidding be experienced, the typical recovery method is to completely release the brakes momentarily to let the wheels spin up and establish an adequate speed reference.

When hydroplaning occurs, which reduces wheel contact and friction, a crosswind will exacerbate the aircraft’s natural tendency to weathervane into the wind. Both smooth runway surfaces and smooth tread tires will induce hydroplaning with lower water depths.

Although the exact depth of water could not be determined, the presence of water on the runway caused the aircraft to hydroplane. This led to a loss of directional control and braking ability and increased the required stopping distance. This condition was exacerbated because the brakes were held on throughout the landing roll and the tires had excessive tread wear.

Tire Wear

In this occurrence, three of the four tires were in excess of 80% worn, while the fourth tire was about 65% worn. On a wet runway, once a tire is about the 80% worn the wet-runway friction-coefficients drop markedly.

Utilizing tires that are more than 80% worn reduces wet-runway traction, thereby increasing the risk of hydroplaning and possible runway overruns.

Wet Runways

Both the macro and microtexture characteristics of a pavement surface can significantly affect its friction values. When TSB investigators touched the surface of runway 11/29, they found it smooth, which is inconsistent with the gritty feeling of a good microtexture. Good microtexture is the principal means of combatting viscous hydroplaning. Both the FAA and ICAO recommend that a complete runway friction survey should include tests at both 65 km/h (macrotexture condition) and 95 km/h (microtexture condition). Even though Advisory Circular (AC) No. 300-008 states that the quality of the runway surface, including the microtexture condition, may contribute to the runway’s slipperiness under wet or dry conditions, TC does not require microtexture testing to be carried out. The practice of not testing the runway surface microtexture increases the risk of wet runway hydroplaning due to an incomplete assessment of the runway’s overall friction characteristics.


The TSB calculated the wear, based on an initial retread depth of 0.43 in. and the average tread depth remaining, on the occurrence aircraft’s no. 1 tire to be about 65%, no. 2 tire about 90%, and the no. 3 and no. 4 tires, shown above, were in excess of 95% worn.

Findings as to causes and contributing factors

  1. The aircraft touched down about 1 850 ft from the threshold, and at a higher than required airspeed, which reduced the available runway length to stop the aircraft.

  2. Excessive tread wear and the wet runway caused the aircraft to hydroplane, which led to a loss of directional control and braking ability, resulting in the aircraft overrunning the runway.

  3. The brakes were not released when the skid occurred, which reduced the effectiveness of the anti-skid system.

Findings as to risk

  1. Utilizing tires that are more than 80% worn reduces wet runway traction, thereby increasing the risk of hydroplaning and possible runway overruns.

  2. The practice of not testing the runway surface microtexture increases the risk of wet runway hydroplaning due to an incomplete assessment of the runway’s overall friction characteristics.

  3. The lack of adequate runway end safety areas (RESA) or other engineered systems or structures designed to stop aircraft that overrun increases the risk of aircraft damage and passenger injuries.

  4. The use of non-grooved runways increases the risk of wet runway overrun due to a reduction in braking characteristics.

  5. If all employees do not fully understand their reporting obligations and have not adopted a safety reporting culture as part of everyday operations, the safety management system (SMS) will be less effective in managing risks.

  6. When an operator’s SMS is not fully effective, there is an increased risk that hazards will not be identified and mitigated.

  7. The lack of clearly defined runway surface condition (RSC) reporting standards related to water on runways increases the risk of hydroplaning.

  8. If cockpit voice recorders (CVR) and flight data recorders (FDR) are not checked in accordance with regulations, there is risk that the recorded data will not be useable and potentially valuable information may not be recorded.

Safety action taken

Operator

Following the occurrence, the operator updated its crew resource management training to include landing distances, braking, wet and contaminated runways, and crosswind landings. Following the occurrence, the operator enhanced the test procedures for FDR recordings.

St. John’s International Airport Authority

Following the occurrence, the St. John’s International Airport Authority implemented an expanded runway friction testing program. This program includes more extensive friction testing, increasing the number of longitudinal test runs at various offset distances from runway centreline and conducting runway macrotexture measurements.

TSB Final Report A11W0152—Continued Visual Flight into Instrument Meteorological Conditions - Collision with Terrain

On October 5, 2011, a Bell 206B helicopter was on a VFR flight from Whitecourt, Alta., to Drayton Valley Industrial Airport, Alta. The flight encountered and continued into instrument meteorological conditions (IMC). The aircraft collided with terrain approximately 1 NM south of Drayton Valley Industrial Airport, at 18:20 MDT, during daylight hours. There was no post-crash fire. The pilot, who was the sole occupant, was fatally injured. No emergency locator transmitter (ELT) signal was received by search and rescue authorities. The TSB authorized the release of this report on October 31, 2012.

Analysis

There was no indication that an aircraft system malfunction contributed to this occurrence. This analysis will focus on the decision-making, operational and environmental factors that contributed to the occurrence.

Two days prior to the occurrence flight, the pilot had decided to terminate a trip and return to base due to deteriorating weather. Regulations, company operational procedures and prior training likely had some influence in that decision-making process. In the case of the occurrence flight, it could not be determined why the pilot chose to deviate from the planned routing.

Once on top, the only recourse was to descend through the cloud to regain visual reference. The pilot did not contact the Edmonton area control centre (ACC) and request assistance, such as vectors to a larger airport. However, had the pilot done so, a descent through cloud would still have been necessary. In addition, there is no indication that the pilot attempted to turn back towards Whitecourt, where the weather was better.

Although the pilot had indicated concern about possible icing, the investigation discounted this possibility, as there likely would have been a loss of control due to tail rotor icing, which would have resulted in a different impact signature.

During the descent through cloud, the pilot was able to control the rotorcraft, but lost awareness of the aircraft's height above ground, and did not arrest the rate of descent prior to impact with terrain. Disorientation or loss of situational awareness could have played a part to some degree.

The pilot was in the habit of not wearing the available shoulder harnesses. These harnesses serve to maintain occupants in an upright position in order to take full advantage of all the crashworthiness features of the aircraft. To what extent this may have contributed to the injuries sustained could not be determined. The fact that the pilot was not wearing a helmet likely would not have been a factor in survivability due to the severity of impact forces.

Findings as to causes and contributing factors

  1. The pilot continued the VFR flight into weather conditions that required descent through cloud to reach destination.

  2. The pilot did not arrest the rate of descent, resulting in a collision with terrain in which the impact forces were not survivable.

Finding as to risk

  1. Not wearing the available shoulder harnesses or a helmet increases the risk of severe injury or death.

Other finding

  1. The ELT switch was found in the OFF position.

Safety action taken

The operator’s pilots have all received human factors training and pilot decision-making training since the accident.

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