Recently Released TSB Reports

Recently Released TSB Reports

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. We encourage our readers to read the complete reports on the TSB Web site. For more information, contact the TSB or visit their Web site at http://www.tsb.gc.ca/. -Ed.

TSB Final Report A05O0146-Engine Power Loss

On July 18, 2005, a float-equipped Cessna 185F was en route to its home base at Orillia,Ont., after two passengers and their belongings were picked up at a remote fishing camp about 21 mi. to the east of Orillia. After takeoff, the aircraft climbed to approximately 1 000ft above ground level(AGL)and proceeded towards Orillia. All engine parameters were normal until a few minutes into the flight, when the engine(Teledyne Continental IO-520-D)lost power. The pilot moved the mixture control to full rich and selected the auxiliary electric fuel pump on. The engine regained power, and the flight continued towards home base, about five miles away. Shortly thereafter, the pilot switched off the auxiliary fuel pump and the engine immediately lost power. The pilot applied full throttle, switched fuel tanks, and re-selected the auxiliary fuel pump on. However, the engine did not regain power.

An emergency landing was performed in a wetland area at 13:08Eastern DaylightTime(EDT). After touchdown, the aircraft travelled a short distance over the soft, wet ground, struck a tree, and came to a stop. One passenger received a minor injury, and all occupants evacuated the aircraft safely. The aircraft was substantially damaged. The pilot was able to maintain radio and cellular telephone communications with another company aircraft flying in the area and with his home base. A short time later, the three occupants were evacuated by a search and rescue helicopter.

Piece of thread sealant in valve seat

Piece of thread sealant in valve seat

Findings as to causes and contributing factors

  1. A piece of thread sealant lodged in the bypass valve of the engine-driven fuel pump created a reduction of fuel pressure, preventing normal engine operation.
  2. A poor electrical connection within the auxiliary fuel pump resulted in intermittent operation of the pump. When the pilot re-selected the pump to provide additional fuel pressure to the engine, it did not operate.

TSB Final Report A05W0222-Engine Torching

On October30,2005, a Boeing737-900 aircraft was scheduled to take off at 07:00Mountain Standard Time(MST), on its first flight of the day, from Calgary International Airport,Alta., to LosAngeles International Airport, Calif. The aircraft was pushed back across the apron from departure Gate 26. Following a normal start on the left engine, the crew initiated a start on the right engine. During the start sequence, the right engine discharged a large quantity of flame and smoke from the tailpipe, with smoke eventually entering the aft cabin. The engines were shut down, and all 113 passengers were evacuated using the emergency slides on the two leftside main doors, away from the right-engine tailpipe fire. The flight crew requested aircraft rescue and firefighting assistance, and the trucks arrived as the passengers were evacuating. By this time, there was no longer any flame or smoke visible. There were no injuries to passengers or crew. Initial examination determined that the fire was contained within the engine flow path(CFM 56-7B26, serialnumber890392). There was no damage to the engine or the aircraft structure.

Findings as to causes and contributing factors

  1. Excessive solder on a jet pipe nozzle in the overhauled electro-hydraulic servo valves(EHSV)reduced the clearance area so that particle contamination allowed binding, resulting in a nozzle position that commanded excessive fuel flow.
  2. The manufacturer's quality assurance monitoring did not detect the excessive solder on the jet pipe nozzle, allowing the nozzle back into service.
  3. Excess unburned fuel, caused by the excessive fuel flow, ignited as it exited the engine and tailpipe, resulting in severe external torching.

Nozzle with a normal profile

Nozzle with a normal profile

Nozzle from occurrence EHSV

Nozzle from occurrence EHSV

Findings as to risk

  1. When the evacuation order was given, the evacuation checklist was not complete and, consequently, the left engine was not yet shut down. When the aft left door was opened and the slide deployed, engine airflow could have resulted in injuries to passengers attempting to use the slide.
  2. The closed cockpit door likely reduced the effectiveness of communications between the cabin and flight deck crews, and prevented the pilots from directly assessing the amount of smoke in the cabin.

Other finding

  1. It is possible that the digital display format for fuel flow had a bearing on the flight crew's ability to detect the abnormal fuel flow during the start of the No. 2 engine.

Safety action taken

Honeywell International Inc.
Honeywell International Inc. inspected all EHSV units returned for overhaul since the occurrence. By June15,2006, 117 returned valves had been inspected with no anomalies detected. The overhaul process was subjected to an internal quality review, and changes were made to prevent a recurrence. As well, the following processes were put in place:

  • training was conducted for all soldering operators and inspectors;
  • peer audits were scheduled quarterly;
  • a quality inspection point was added for all overhauled spring solder joints;
  • process verification audits were scheduled on an annual basis; and
  • rejected and reused components were to be completely segregated during disassembly, cleaning, and reassembly.

Operator
The operator revised the company's training program to ensure that flight crews fully complete the emergency evacuation checklist before ordering an evacuation.

The Calgary Airport Authority
Operations personnel from The Calgary Airport Authority and tenants of the Calgary International Airport discussed the hazards and mitigations associated with operation of ground vehicles in the proximity of deplaning passengers during emergency situations.

TSB Final Report A05P0298-Engine Failure-Descent into Terrain

On December20,2005, at 18:34Pacific Standard Time(PST), a Mitsubishi MU-2B-36 aircraft took off from Runway15 at the Terrace,B.C., airport for a courier flight to Vancouver,B.C. The left engine lost power shortly after takeoff. The aircraft descended, with a slight left bank, into trees and crashed about 1 600ft east of the departure end of Runway15, on a heading of 072° magnetic. The aircraft was destroyed by the impact and a post-crash fire, and the two pilots were fatally injured.

Engine Failure—Descent into Terrain

Findings as to causes and contributing factors

  1. During the takeoff, the left engine combustion chamber plenum split open due to a fatigue crack. The rupture was so extensive that the engine flamed out.
  2. The crew did not feather the left engine or retract the flaps, and the aircraft entered a moderate lefthand turn after takeoff; the resulting drag caused the aircraft to descend until it contacted trees.
  3. The first officer's flying skills may have been challenged during the handling of the engine failure, and the checklist was conducted out of sequence, suggesting that there may have been uncertainty in the cockpit. A contributing factor may have been the captain's unfamiliarity with handling an emergency from the right seat.
  4. The use of flap 20 for takeoff, although in accordance with company policy, contributed to the difficulty in handling the aircraft during the emergency.

Findings as to risk

  1. The TPE331-series engine plenum is prone to developing cracks at bosses, particularly in areas where two bosses are in close proximity and a reinforcing weld has been made. Cracks that develop in this area cannot necessarily be detected by visual inspections or even by fluorescent penetrant inspections(FPI).
  2. Because the wing was wet and the air temperature was at 0°C, it is possible that ice may have formed on top of the wing during the takeoff, degrading the wing's ability to generate lift.
  3. Being required to conduct only flap 20 takeoffs increases the risk of an accident in the event of an engine problem immediately after takeoff.

Other finding

  1. The plenum manufactured with a single machined casting, incorporating the P3 and bleed-air bosses, is an improvement over the non-single casting boss plenum; however, cracks may still develop at bosses elsewhere on the plenum.

Safety action taken

On July6,2006, the TSB issued Safety Advisory A060025-1 suggesting that Transport Canada(TC) may wish to remind MU-2B and other twin-engine operators of the importance of ensuring that the required checklist items are completed immediately after recognition that an engine has failed on takeoff.

On September8,2006, TC issued Service Difficulty Advisory(SDA)AV-2006-07 regarding Mitsubishi MU-2B cracked combustor plenums(Honeywell TPE-331-6-252Mengines). The SDA recommended compliance with the manufacturer's(Honeywell)Service Bulletin(SB)TPE331-72-2023 to change the combustion chamber from a 3102613-1 (multicasting boss plenum)to a 3102613-2 (single-casting boss plenum). TC also recommended that maintenance personnel be extra attentive to boss welds when inspecting TPE331-series engines for plenum cracks.

On November14,2006, the TSB re-issued SafetyAdvisoryA060025-1 suggesting that TC may wish to remind MU-2B and other operators of the effect of flap settings on achieving a required climb gradient following an engine failure in varying ambient conditions.

On May18,2007, the TSB issued Safety Advisory A06P0298-D2-A2 (Cracks in TPE331-Series EnginePlenum). The advisory described the history of plenum cracking with the TPE331-series engine, particularly in areas where two bosses are in close proximity and a reinforcing weld has been made. Cracks that develop in this area cannot necessarily be detected by visual inspections or even by FPIs. The advisory suggested that TC may wish to advise commercial operators of the circumstances of this occurrence. Additionally, it suggested that TC may wish to consider the requirement for discussion with the U.S. Federal Aviation Administration(FAA)regarding the effectiveness of the maintenance instructions for identifying cracks in the TPE331-series engine plenum.

TSB Final Report A06F0014-Misaligned Takeoff

On January30,2006, an Airbus A319-114 with 84passengers and 5crew members on board, was on a scheduled flight from Las Vegas,Nev., to Montréal, Que. The aircraft was cleared to depart Runway25R and the crew commenced a rolling takeoff at 00:15Pacific Standard Time(PST). Shortly thereafter, both members of the flight crew realized that the aircraft was rolling on the asphalt runway shoulder instead of on the runway centreline. At approximately 65knots indicated airspeed(KIAS), the pilot flying applied left rudder to realign the aircraft with the runway centreline and completed the takeoff. The flight continued to Montréal, where an uneventful landing was carried out. During the flight to Montréal, the crew advised company dispatch of the departure occurrence. Dispatch advised the Las Vegas tower that the aircraft may have damaged some runway edge lights during the take-off roll. Three runway edge lights were found damaged. The only damage noted on the aircraft was a cut on the left-hand nose-wheel tire. There were no injuries.

Finding as to causes and contributing factors

  1. The pilot flying likely relied on peripheral vision to taxi the aircraft because of the requirement to maintain separation with the aircraft departing ahead. This, combined with the aerodrome markings, resulted in the misalignment of the aircraft and the initiation of the takeoff from the asphalt runway shoulder instead of the runway centreline.

Findings as to risk

  1. A rolling takeoff reduces the crew's time for conducting a thorough outside visual check and verifying runway alignment before initiating the take-off roll.
  2. Taxiway B1 and A2 centrelines curve onto the runway edge line. At night, this could result in pilots aligning their aircraft with the runway side stripe marking instead of with the runway centreline.
  3. This occurrence was reported to company dispatch and air traffic services two hours after the event. During that time, debris left by the broken lights could have posed a hazard for other aircraft using Runway 25R.

Other finding

  1. The other three similar events that happened on Runway 25R at the Las Vegas McCarran International Airport(KLAS)were not reported. Failure to declare such events deprives investigators of important data that could help to identify the contributing factors that lead to this type of event.

Safety action taken

The Las Vegas Airport Authority made modifications to the taxiway markings following the occurrence. At Taxiway B1, the radius of the taxiway centreline was extended past the runway edge line and now meets with the runway centreline in the displaced threshold arrow area. At Taxiway A2, the radius of the taxiway centreline that curves to the runway edge line was erased, and the taxiway centreline now extends to the threshold markings.

Circle shows Taxiway B1 centreline

Photo:Google Maps

Circle shows Taxiway B1 centreline as it curved into the
runway edge line, prior to the modification

Circle shows Taxiway B1 with the radius of the taxiway centreline

Photo:Google Maps

Circle shows Taxiway B1 with the radius of the taxiway
centreline extending past the runway edge line and meeting
with the runway centreline in the displaced threshold
arrow area, after the modification

TSB Final Report A06P0036-Runway Overrun-Collision with Terrain

On March8,2006, a PiperPA-31-350 Chieftain departed from its home base at Vancouver,B.C., with two crew members on board. The aircraft was being repositioned to Powell River, B.C.(a 30-min flight), to commence a freight collection route. On arriving at Powell River, the crew joined the circuit straight-in to a right downwind for a visual approach to Runway 09. A weather system was passing through the area at the same time and the actual local winds were shifting from light southwesterly to gusty conditions(11 to37kt) from the northwest. The aircraft was lower and faster than normal during final approach, and it was not aligned with the runway. The crew completed an overshoot and set up for a second approach to the same runway.

On the second approach, at about 16:39Pacific Standard Time(PST), the aircraft touched down at least halfway down the wet runway and began to hydroplane. At some point after the touchdown, engine power was added in an unsuccessful attempt to abort the landing and carry out an overshoot. The aircraft overran the end of the runway and crashed into an unprepared area within the airport property. The pilot-in-command suffered serious injuries and the first officer was fatally injured. A local resident called 9-1-1 and reported the accident shortly after it occurred. The pilot-in-command was attended by paramedics and eventually removed from the wreckage with the assistance of local firefighters. The aircraft was destroyed, but there was no fire. The emergency locator transmitter(ELT)was automatically activated, but the signal was weak and was not detected by the search and rescue satellite.

Runway Overrun

Findings as to causes and contributing factors

  1. The downwind condition on approach contributed to the aircraft landing long and with a high ground speed. This, in combination with hydroplaning, prevented the crew from stopping the aircraft in the runway length remaining.
  2. When the decision to abort the landing was made, there was insufficient distance remaining for the aircraft to accelerate to a sufficient airspeed to lift off.
  3. The overrun area for Runway 09 complied with regulatory standards, but the obstacles and terrain contour beyond the overrun area contributed to the fatality, the severity of injuries, and the damage to the aircraft.

Finding as to risk

  1. Alert Service BulletinA25-1124A(dated 01 June 2000), which recommended replacing the inertia reel aluminium shaft with a steel shaft, was not completed, thus resulting in the risk of failure increasing over time.

Other findings

  1. The weather station at the Powell River airport does not have any air-ground communication capability with which to pass the flight crew timely wind updates.
  2. The decision to make a second approach was consistent with normal industry practice, in that the crew could continue with the intent to land while maintaining the option to break off the approach if they assessed that the conditions were becoming unsafe.

Safety action taken

The TSB forwarded a Safety Information Letter, dated 18August2006, to the Powell River airport operator. The letter addressed the terrain contour beyond the overrun area for Runway 09, reflecting the third item under "Findings as to causes and contributing factors."

TSB Final Report A06O0206-Mid-Air Collision

On August4,2006, two light airplanes collided in midair approximately 1 NM west of the town of Caledon,Ont. Both airplanes were operating in accordance with visual flight rules(VFR)in Class E airspace. The collision involved a Cessna172P airplane operated by the Brampton Flying Club and being flown by an instructor and student, and a Cessna182T airplane being flown by its owner. The Cessna172P was southeastbound in a gradual descent, wings level. The Cessna182T was northbound in straight and level flight. The angle between the tracks of the two airplanes was approximately120°.

During the collision, the right wing was torn from the Cessna182T and the airplane became uncontrollable. The Cessna172P sustained damage to the nose and cockpit areas. Both airplanes crashed in close proximity to the point of collision. The three occupants of the airplanes received fatal injuries and both airplanes were destroyed. There was a small post-impact fire as a result of debris from one airplane severing an electrical power line. There was no fire in the main wreckage of either airplane. The accident took place at12:34 Eastern Daylight Time(EDT)at 43°51'29.6"N, 080°1'12.8"W.

Airplane flight paths

Airplane flight paths

Findings as to causes and contributing factors

  1. Toronto,Ont., airspace design provides only limited vertical space beneath ClassC airspace northwest of Toronto. Consequently, both airplanes were at the same altitude when their tracks intersected, and they collided.
  2. There are inherent limitations and residual risk associated with the see-and-avoid principle; as a result, neither airplane saw the other in time to avert a mid-air collision.

Field of view for the crew from each airplane

Field of view for the crew from each airplane

Finding as to risk

  1. There is a high residual risk of failure inherently associated with the unalerted see-and-avoid principle as the sole defence against mid-air collision in congested airspace.

Other findings

  1. A technological means of alerting pilots to potential conflicts would augment the current see-and-avoid approach to averting mid-air collisions.
  2. Canadian air traffic control radars do not support traffic information service(TIS); therefore, aircraft equipped with TIS cannot obtain traffic advisory information.
  3. Light aircraft in Canada are not required to carry traffic alert and collision avoidance systems(TCAS)or any other form of traffic alerting system.
  4. As a result of technological advances, practicable light aircraft/glider collision warning devices and secondary surveillance radar(SSR)transponders are being developed.
  5. There has been little progress in implementing recommendations made by a safety review of VFR operations in Toronto airspace following a previous mid-air collision.

Safety action taken

NAVCANADA
NAVCANADA has taken the following actions since this accident, some of which are within the framework of a level of service review of the Montréal-Toronto-Windsor airspace corridor:

  • In addition to the Claremont training area depictions, the latest Toronto area VFR charts(June2007)have additional symbols depicting current parachute, ultralight, and flight training areas.
  • The Toronto VFR terminal area(VTA)chart(July2007)contains a new depiction to illustrate the final approach areas for the instrument flight rules(IFR)approaches serving Hamilton, with a cautionary note that pilots should be particularly vigilant in those areas for IFR aircraft on approach. The next cycle of the Canada Flight Supplement(CFS)will contain a number of these enhancements as well.
  • On July 5,2007, the Class E airspace above 6500ft within 65NM of Toronto was designated as mandatory transponder airspace.
  • Through2006–2007, NAVCANADA, in conjunction with Transport Canada(TC), has continued to provide briefing/information sessions to VFR pilots about operations in the Toronto area.
  • Through the airspace and services reviews consultative workgroups, NAVCANADA continues to facilitate a dialogue on what types of VFR routes and information would best serve the VFR community, including discussion about the information contained on the back of United States VTA charts, common area frequencies, publication of VFR practice areas and transition routes.
  • A comprehensive flight planning Web page has been set up, including aerodrome diagrams and other flight planning products, ensuring that pilots have free access to comprehensive and up-to-date aeronautical data.
  • An airspace and services review has been initiated in the Montréal-Toronto-Windsor corridor.

Brampton Flying Club
The Brampton Flying Club has taken the following safety actions:

  • A pulse light system has been installed in all nine Cessna172s and one Piper Seminole of the Brampton Flying Club fleet to enhance visibility to other aircraft. The remainder of the fleet will also be fitted with pulse lights.
  • The Brampton Flying Club has met with NAVCANADA and requested a modest raising of the floor of ClassC airspace to the north and west of the Brampton airport, and that the practice area be identified in a manner similar to the Claremont training area on the Toronto VTA and VFR navigation charts(VNC)and in the CFS.

Action required

Vertical Structure of Airspace
Research has shown that the probability of two aircraft being on a collision course is essentially a function of traffic density, and the risk of collision is proportional to the square of this density. Measures such as improving aircraft conspicuousness, pilot scanning technique, and pilot traffic awareness can reduce risk, but they do not overcome the underlying physiological limitations that create the residual risk associated with unalerted see-and-avoid.

The current design of Toronto airspace in the vicinity where this accident occurred results in a concentration of traffic in a very small altitude band, immediately below the floor of ClassC airspace, and immediately outside the radius at which the floor of ClassC airspace steps down toward the Toronto/Lester B. Pearson International Airport. The combination of a ground elevation of 1 400ft above sea level(ASL), flight at or above 1 000ft above ground level(AGL), and a ClassC floor of 2 500ft ASL results in all traffic being concentrated vertically at the single altitude of 2 400ftASL. Changing the vertical structure of the airspace is one way of reducing this traffic concentration.

Radar data reviewed for this area during a 10-day period around the accident indicated a heavy volume of VFR traffic below the ClassC floor, and several occasions where aircraft were within about 1 500ft horizontally and 200ft vertically of each other. In this and other congested airspaces, it has been shown that the see-andavoid principle for VFR aircraft is not always sufficient to ensure the safety of flight. Therefore, there continues to be a high risk of a mid-air collision between aircraft operating under the VFR principle in that airspace.

Therefore, the TSB recommends that:

The Department of Transport, in co-ordination with NAVCANADA, take steps to substantially reduce the risk of collision between VFR aircraft operating in Class E airspace surrounding the Toronto/Lester B. Pearson International Airport.

A08-03

Safety concern

Collision-Protection Systems
At the present time, a large number of VFR-only aircraft are not equipped with Mode C transponders-devices that can alert pilots to other aircraft in their vicinity. Furthermore, the lack of other, available, and installed technological methods of alerting VFR pilots to the presence of other aircraft increases the risk of a mid-air collision, especially in congested airspace. A meaningful improvement to the ability to see-and-avoid other VFR aircraft requires a practicable, affordable method of alerting pilots to the proximity of conflicting traffic.

Recent developments in Europe, specifically with respect to low-cost, low-power, lightweight Light Aviation SSR Transponder(LAST)technology and collision-protection systems such as FLARM [FLARM is a trade name inspired by and derived from "FLight AlaRM."] that are compatible with automatic dependent surveillance broadcast(ADS- B), indicate that technological solutions are emerging that can accomplish both of these objectives. These new systems offer a means to reduce the risk of future mid-air collisions, provided they are integrated into the Canadian regulatory, airworthiness, airspace and navigation framework, and supported by general aviation.

Aircraft operating under VFR in congested airspace using solely the see-and-avoid principle as a means of avoiding one another run an increased risk of collision, as this and other mid-air accidents have demonstrated. This single point of defence has shown that it is not sufficient to ensure safety; however, the TSB believes that emerging technology that may be an affordable option to reduce this risk merits a serious look.

The TSB is concerned that, until technological solutions such as on-board collision-protection systems are mandated, a significant risk of collision between VFR aircraft will continue to exist in congested, high-density airspace areas in Canada. The TSB notes that the risk of collision will increase as this traffic continues to grow, and see-and-avoid remains the primary means of defence. In addition, the TSB recognizes that technological innovation is creating potential solutions that are both viable and economical.

The TSB appreciates that TC must examine all potential solutions before it can decide how best to recommend or mandate the adoption of one or more systems. On this basis, the TSB requests that TC take a lead role, in co-operation with industry, in examining technological solutions, with the eventual aim of broad-scale adoption.

There is a lot more to read on this extensive report, so we encourage readers to visit the TSB Web site. -Ed.

TSB Final Report A06C0154-Loss of Control-In-Flight Break-Up

On September24,2006, a Bell204B helicopter was being used to conduct external load operations south of Stony Rapids,Sask., slinging drill rods between drill sites. Approximately three minutes into the flight, the pilot radioed that his side bubble window door had come open and that he was having difficulty holding the door.

Loss of Control—In-Flight Break-Up

The pilot released the sling load and the helicopter was observed climbing in a steep nose-up attitude before momentarily stopping on its tail, then dropping nose down. As the helicopter descended toward the ground, there was an explosion. The helicopter crashed approximately 22 NM southwest of Stony Rapids and was destroyed by impact forces and a post-crash fire.

The pilot, the sole occupant of the helicopter, was killed. The crash occurred during daylight hours at 18:11 Central Standard Time(CST).

Findings as to causes and contributing factors

  1. The pilot's left-side bubble door opened during flight, likely because it was not closed and properly latched.
  2. In the pilot's preoccupation with the open door, it is likely that he allowed the helicopter to enter a low-g condition, which led to mast bumping and the in-flight break-up of the helicopter.

Safety action taken

As a result of this occurrence, the operator has included additional documented training in its initial ground briefings to cover inadvertent door openings in flight and has fitted all of its helicopters with an automatic pneumatic door opener. This will prevent the doors from being closed unless they are fully latched.


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