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 A04O0016-Nose Wheel Axle Failure

On January 19, 2004, at approximately 14:10 Eastern Standard Time (EST), an Airbus A321-214 landed on Runway 06L at Lester B. Pearson International Airport, Toronto, Ont., after a flight from Montréal, Que. While taxiing to the terminal, the flight crew heard a noise from the nose landing gear area. As the aircraft turned onto the lead-in line at the gate, the ground marshallers observed that the right-hand nose wheel was missing, and immediately had the aircraft stopped. Maintenance personnel inspected the nose landing gear and determined that it was safe for the aircraft to proceed to the gate. Airport authorities closed Runway 06L to inspect for aircraft components and landing surface damage. The nose wheel was subsequently located on the ramp. There were no injuries and damage to the aircraft was limited to the nose landing gear assembly. The damaged components were removed from the aircraft and shipped to the TSB Engineering Branch for examination.

Aircraft at the gate

Aircraft at the gate, shortly after arrival

Findings as to causes and contributing factors

  1. The nose wheel right inboard roller bearing failed. Itis likely that the lack of lubrication, as a result of the grease dam being dislodged from its normal position, was a contributing factor.
  2. The friction temperatures created by the failed roller bearing exceeded the cadmium melting point. Cadmium penetrated and weakened the intergranular structure of the nose landing gear axle, causing it to fail due to liquid metal embrittlement.

Finding as to risk

  1. The dislodged inner-bearing grease dam allowed grease to migrate from the inboard roller bearing of the right nose wheel to the inside of the nose wheel assembly. A reduction in lubrication increases the cage loads and may lead to bearing failures.

Safety action taken

The operator has taken steps to have the axles for its nose landing gears coated with SermeTel® to reduce the likelihood of axle failures from cadmium infusion as a result of high friction heat generated from bearing failures. SermeTel® is an anti-corrosive and chemical-resistant base applied as an initial coating prior to decorative coatings of epoxy resin and polyurethane paints. It is an inorganic formula, consisting of an aqueous carrier containing a mixture of magnesium chromate, phosphates and silicates, and aluminum powder.

The operator has also issued a maintenance alert and revised its wheel installation job card to stress the importance of a wheel inspection prior to installation, and to ensure the recommended wheel installation tools and torques are used in accordance with the aircraft maintenance manual (AMM). The operator's wheel shop manuals were revised to raise awareness of the importance of grease dams and seal installations.

In May 2004, Goodrich released Service Letter 1991 that recommends using Mobil SHC-100 grease for the wheel bearings due to its superior adhesion properties, which also increase corrosion protection and bearing lubrication. Goodrich also issued Service Bulletin 3-1531-32-3 in July 2004, with new inspection procedures for bearing grease seals on Airbus A318, A319, A320 and A321 aircraft.

TSB Final Report A05Q0178-Capsizing at Takeoff

On September 29, 2005, a Cessna 185 on floats was to make a scenic flight following visual flight rules (VFR) with a pilot and five passengers on board. The seaplane left the company's wharf at Lac Ouimet, Que., then taxied on the surface of the lake for about 500 m. When it reached the take-off area, the seaplane turned left to face into the wind in preparation for takeoff. At approximately 15:10 Eastern Daylight Time (EDT), as the pilot was applying the throttle, the seaplane tipped to the right, the nose of the right float dug into the water, the propeller hit the surface of the lake, and the aircraft capsized. The pilot and four passengers escaped from the cabin. A seaplane from the company and a neighbouring resident in a boat headed to the survivors right away. The survivors were rescued within seven minutes of the accident. The passenger in the right front seat was unable to escape from the submerged cabin and drowned.

Finding as to causes and contributing factors

  1. The combined effects of the wind, centrifugal forces, water resistance, starting the takeoff in a crosswind, and the attempt to regain control by applying full throttle and full rudder, contributed to the capsizing of the seaplane.

Findings as to risk

  1. The passengers were not given a safety briefing before the flight. Consequently, they did not know the location of the lifejackets.
  2. The instructions printed on the aircraft's safety briefing card about how to open the passenger door were incorrect, which could have compromised the safe egress of occupants.
  3. The form for recording the flight times, flight duty times, and rest periods for the pilot had not been updated for almost a month. This did not allow the company manager to monitor the pilot's hours.
  4. Neither the pilot nor the front passenger was wearing his shoulder harness, as required by regulations. This could have increased the risk of injury.

Other finding

  1. During the investigation, the TSB identified three operational deficiencies that Transport Canada had noted earlier in August 2002, and reported to the company. The deficiencies concerned the monitoring of pilot schedules, the use of shoulder harnesses, and the pre-flight safety briefing.


TSB Final Report A05C0187-Loss of Control and Collision with Terrain

On October 6, 2005, a Cessna 208B Caravan departed from Winnipeg, Man., on a freight flight to Thunder Bay,Ont., with one pilot on board. The aircraft departed at 05:37 Central Daylight Time (CDT). Shortly after takeoff, the flight was cleared to 9 000 ft above sea level (ASL), and direct to Thunder Bay. Several minutes later, the aircraft began a descent and the pilot requested an immediate return to the Winnipeg International Airport. The aircraft turned right to a southwesterly heading, and then the descent continued below radar coverage. After a very steep descent, it crashed on railway tracks in Winnipeg. The pilot suffered fatal injuries, and the aircraft was destroyed by impact forces and an intense post-crash fire.

Loss of Control and Collision with Terrain

Findings as to causes and contributing factors

  1. The aircraft departed at a weight exceeding the maximum take-off weight and the maximum weight for operation in icing conditions.
  2. After departure from Winnipeg, the aircraft encountered in-flight icing conditions in which the aircraft's performance deteriorated until the aircraft was unable to maintain altitude.
  3. During the attempt to return to the Winnipeg International Airport, the pilot lost control of the aircraft, likely with little or no warning, at an altitude from which recovery was not possible.

Findings as to risk

  1. Aviation weather forecasts incorporate generic icing forecasts that may not accurately predict the effects of icing conditions on particular aircraft. As a result, specific aircraft types may experience more significant detrimental effects from icing than forecasts indicate.
  2. Bulk loading prevented determining the cargo weight in each zone, resulting in a risk that the individual zone weight limits could have been exceeded.
  3. The aircraft's centre of gravity (CG) could not be accurately determined, and may have been in the extrapolated shaded warning area on the CG limit chart. Although it was determined that the CG was likely forward of the maximum allowable aft CG, bulk loading increased the risk that the CG could have exceeded the maximum allowable aft CG.
  4. The incorrect tare weight on the Toronto cargo container presented a risk that other aircraft carrying cargo from that container could have been inadvertently overloaded.

Other findings

  1. The pilot's weather information package was incomplete and had to be updated by a telephone briefing.
  2. The operator's pilots were not pressured to avoid using aircraft de-icing facilities or to depart with aircraft unserviceabilities.
  3. The aircraft departed Winnipeg without significant contamination of its critical surfaces.
  4. The biological material on board the aircraft was disposed of after the accident, with no indication that any of the material had been released into the ground or the atmosphere.
  5. The fact that the aircraft was not equipped with flight data recorder (FDR) or cockpit voice recorder (CVR) equipment limited the information available for the occurrence investigation and the scope of the investigation.

Safety action taken

The safety actions section of this major investigation report is unfortunately too long to reproduce entirely in the Aviation Safety Letter (ASL); therefore, our readers are strongly encouraged to read the entire report on the TSB Web site at: www.tsb.gc.ca/eng/rapports-reports/aviation/2005/a05c0187/a05c0187.asp.

Suffice it to say that the focus is largely on flight into icing conditions, on the Cessna 208 in particular, and also on weight and balance issues. Several of the safety actions are also related to the investigation into the Pelee Island, Ont., crash of a Cessna 208 on January 17, 2004 (TSB file A04H0001). This report was summarized in ASL 4/2006. -Ed.



TSB Final Report A05A0155-Collision with Water

On December 7, 2005, a Messerschmitt-Boelkow-Blohm (MBB) BO-105 helicopter was being used for various tasks associated with the upkeep and operation of lighthouse and coastal navigation facilities in the Burin Peninsula area of Newfoundland and Labrador. While returning to Marystown, N.L., in the late afternoon of December 7, 2005, with one pilot and one passenger on board, the helicopter encountered heavy snow showers, and at about 16:28 Newfoundland Standard Time (NST), the helicopter crashed into the water of Mortier Bay, east of Marystown. Both the pilot and the passenger survived the water impact and escaped from the helicopter. However, the pilot perished from hypothermia, and the passenger drowned.

Aircraft during recovery, with cabin largely intact

Aircraft during recovery, with cabin largely intact

Findings as to causes and contributing factors

  1. The helicopter encountered a heavy snow shower, and while attempting to fly out of the snow, the pilot likely became disoriented.
  2. The pilot lost control of the helicopter when the tail broke off after contacting the water during a rapid flare.
  3. The survival equipment fitted to the helicopter sank with it, and was not available to aid the survivors after the accident.
  4. The occupants of the helicopter were not wearing sufficient personal survival equipment to enhance their potential survival in the frigid water.

Findings as to risk

  1. Although the life raft mount had been previously identified as a potential head strike hazard, the passenger was seated in the front seat without head protection.
  2. At the time of the occurrence, the operator's management had not taken steps to mitigate the life raft mount head strike hazard.
  3. The life raft mount failed, pinning the life raft against the centre rear passenger seat.
  4. The emergency locator transmitters (ELT) on board sank to the bottom of the Bay and were not able to signal search and rescue (SAR) of the accident. Therefore, SAR efforts did not begin until one hour after the flight's planned estimated time of arrival (ETA).
  5. The pilot's egress was impeded by a direct-to-airframe helmet cord connection.
  6. None of those who flew in the helicopter on the day of the accident were provided with immersion suits, nor were such suits required by the regulator or the operator.
  7. None of those who flew in the helicopter on the day of the accident had received helicopter emergency egress/water survival training, nor was such training required by the regulator or the operator.
  8. At the time of the accident, the operator had not adequately addressed several identified operational shortcomings.
  9. The frequency of accidents and serious occurrences, the recurrence of identified operational shortcomings, and the lack of progress in the mitigation of several identified deficiencies are matters of concern that suggest organizational shortcomings with the operator.

Other finding

  1. The underwater locator beacon (ULB) did not transmit a detectable acoustic signal.

Safety action taken

Transportation Safety Board of Canada (TSB)
On March 20, 2006, the TSB sent a Safety Information Letter to Transport Canada Civil Aviation (TCCA) and to the operator regarding the signal failure of the ULB.

On March 28, 2006, the TSB sent a Safety Advisory to the operator suggesting that it consider the need to revise its mandatory operations manual requirements for immersion suit use to include the more relevant risk factors related to its helicopters' performance characteristics and operating environment.

Survival equipment on the accident helicopter was installed as required by regulation, yet it was not available to assist the survivors after the accident. On May 9,2006, the TSB sent a Safety Advisory to the operator suggesting that it consider the adequacy of its helicopter survival equipment installations so as to improve occupant survivability in a capsized helicopter event.

With respect to direct-to-airframe helmet cord connections, other operators may have aircraft with these connection types and may be unaware that these connections can impede egress in an emergency. On May 9, 2006, the TSB sent a Safety Advisory to TCCA suggesting that it advise the aviation community that these connection types may impede egress and that an intermediate cord can help mitigate this hazard. In response to this Safety Advisory, TCCA published an article in the ASL 4/2006, explaining the egress hazard related to direct-to-airframe helmet cord connections and suggesting the use of intermediate cords to mitigate the hazard.

On May 9, 2006, the TSB sent a Safety Advisory to the operator suggesting that, as part of its review of the life raft mounting bracket Limited Supplemental Type Certificate, it may wish to conduct an analysis of the structure so as to improve its ability to withstand survivable impact forces, particularly rearward. Also, the Safety Advisory suggested that the operator may wish to consider steps to prevent the mounting bracket and life raft from jamming against the passenger seat belt mounting bolts, should a failure occur.

On June 2, 2006, the TSB sent a Safety Advisory to the operator suggesting that it re-evaluate all levels of its organization so as to become more proactive in identifying risks and deficiencies, and more responsive in communicating and mitigating already identified risks associated with its operations.

Helicopter Operations Safety Working Group
The operator and the Canadian Coast Guard (CCG) have established a Helicopter Operations Safety Working Group to review safety equipment, training, and procedures, and to make recommendations for improvements. This group has taken action on passenger helmets and survival equipment, and is reviewing the policy on wearing immersion suits as well as helicopter egress training. As a result of the efforts of the joint working group, the following actions have occurred:

  • Lifejackets have been standardized for passengers and crews, and reflective tape is to be added to the edging of the cover of the jackets and a large orange patch added to the back.
  • Laser flares have been purchased and sent out to the CCG bases to be attached via a cord and rings to each of the standardized high-visibility Switlik lifejackets, model HV-35C, also identified as S7200-2, and inserted in the customized pouch.
  • Helmets have been purchased and issued for front seat passengers in all helicopters, and their use is mandatory in CCG helicopters.
  • The installation of a fixed intermediate helmet cord for both front seat positions in all BO-105 helicopters is nearing completion.

The operator
The operator is in the process of implementing a safety management system (SMS), adding an assistant chief pilot-helicopter position and a flight operation quality assurance position, all intended to improve, where necessary, existing communication, documentation, and risk assessment practices. Proposals have been generated for modifying the life raft rack to prevent head injuries.

Underwater locator beacon (ULB)
All of the operator's ULBs within the batch of serial numbers affected by the Dukane recall have been replaced. To determine the extent of the delamination problem, the manufacturer cold-tested the 11 beacons returned by the operator. One other beacon was found to have failed in a similar manner. The manufacturer is attempting to determine the cause of the metal delamination and the potential scope of the failure. Once this has been accomplished, the manufacturer will consider a further course of action.


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