Air transportation safety recommendation A19-01
Definition of “safety belt”
On 14 December 2017, a Hydro One Networks Inc. Airbus Helicopters AS 350 B2 helicopter (registration C-GOHS, serial number 3240) equipped with an external platform, was transporting crews of power line technicians between a staging area and transmission towers in an area located 8 nautical miles north-northeast of Tweed, Ontario.
At 1144 Eastern Standard Time, the pilot picked up a crew of 3 power line technicians near the bottom of a tower for a return flight to the staging area. It had become common practice for power line technicians to attach tool bags and other small items to the external platform for flights to and from work sites. In line with this practice, the technicians attached a few items to the platform while boarding the helicopter, and then took their seats in the aft cabin.
The practice of carrying external loads attached to the platform was not a formalized procedure at the company and, as a result, adequate controls were not in place to ensure that these objects were properly stored or secured. Consequently, an empty canvas supply bag with an attached carabiner that was being carried on the platform was not adequately secured before the helicopter departed for the return flight to the staging area.
When the helicopter was 0.26 nautical miles from the staging area, the canvas bag separated from the platform and struck the helicopter's tail rotor, causing significant damage, severe imbalance, and intense vibration.
Shortly after, while the pilot was attempting to land, the helicopter's tail rotor, tail rotor gearbox, and vertical fin separated from the helicopter. The helicopter became uncontrollable and collided with terrain. The 3 power line technicians were unrestrained and became separated from the helicopter, either slightly before or during the impact, and received fatal injuries from contact with the helicopter or the surrounding terrain. The pilot was fatally injured on impact. The helicopter was destroyed.
The Board concluded its investigation and released report A17O0264 on 30 October 2019.
TSB Recommendation A19-01 (October 2019)
All of the rear bench seats in the occurrence helicopter were equipped with 4-point detachable safety belts consisting of a lap strap and an automatic locking (inertia reel) shoulder harness. However, before the occurrence flight, the shoulder harness portions of these safety belts were rolled up and taped with electrical tape, which prevented them from being used.
Subsection 101.1(1) of the CARs defines a safety belt as “a personal restraint system consisting of either [emphasis added] a lap strap or a lap strap combined with a shoulder harness.” Based on this definition, Hydro One Networks Inc. considered that it would be in compliance with the regulations that required the use of safety belts if occupants wore either the lap strap alone, or the lap strap combined with the shoulder harness.
From 1990 to 2018, the TSB has investigated many accidents involving aircraft that were equipped with detachable shoulder harnesses where it was determined that the harnesses were not being worn at the time of the accident (Appendix B). Of the 62 accidents identified, 33 were fatal, resulting in 68 deaths. Of those 68 deaths, 37 were individuals who had not been wearing the available shoulder harness. Although the survivability of these 62 accidents varied, the use of shoulder harnesses in many cases could have improved the odds of survival and egress.
Passengers who are not adequately restrained during a survivable accident, particularly when the main passenger compartment remains relatively intact, are at greater risk of receiving serious or fatal injuries than passengers who are adequately restrained. While the interpretation of the regulations was not the only reason for not wearing the shoulder harness in the cases examined, in this case, the ambiguity did affect their use.
TC attempted to clarify the regulations in Aviation Safety Letters 4/2013 and 1/2018, and Advisory Circular 605-004 (November 2014). However, if regulations are not clear in requiring the use of all available components of a safety belt, shoulder harnesses may not be used as intended, increasing the risk of injury or death.
Therefore, the Board recommended that
the Department of Transport amend the Canadian Aviation Regulations to remove any ambiguity associated with the definition of “safety belt”
TSB Recommendation A19-01
Transport Canada’s response to Recommendation A19-01 (January 2020)
Transport Canada (TC) agrees with aviation safety recommendation (A19-01).
In December of 2019 TC began to conduct a preliminary assessment of the regulatory impact of changing the definition of “safety belt”. The assessment is expected to be completed in early spring 2020.
The assessment includes: a review of the definition in the Canadian Aviation Regulations (CARs) and an analysis of the potential consequences of this definition change to other parts of the regulations. Once consultation with stakeholders is conducted and the most appropriate mechanism for undertaking this recommended change is determined, the regulatory work to amend the definition will commence.
TC will be able to provide a more detailed timeline for this change upon completion of the preliminary analysis. If the change to the definition is deemed to have minimal impact, then the change may be pursued using the Miscellaneous Amendments Regulations (MAR) process. However, if potential consequences to other parts of the CARs are identified, the change will need to follow the full federal regulatory development process.
In the meantime, as described in the investigation report, TC has already taken mitigating measures to encourage the proper use of safety belts. TC began informally consulting with stakeholders on the potential impact of the recommended change in the margins of the Helicopter Association of Canada (HAC) annual meeting in November 2019. In addition, TC has published guidance material concerning the use of safety belts in Aviation Safety Letters (ASL) 4/2013Footnote 1 and 1/2018Footnote 2, and Advisory Circular (AC) 605-004Footnote 3. Also, more recently, TC has published Civil Aviation Safety Alert (CASA) 2018-02Footnote 4 reminding operators of the correct use of passenger seatbelts and the importance of securing cargo.
TSB assessment of Transport Canada’s response to Recommendation A19-01 (March 2020)
In its response, Transport Canada (TC) indicated that it agrees with Recommendation A19-01 and that it has begun assessing the regulatory impact of changing the definition of “safety belt” in subsection 101.1(1) of the Canadian Aviation Regulations (CARs). This assessment includes the possible effects the modification would have on other parts of the regulations.
This assessement will determine the process TC will have to follow. Once the impact of the definition change has been determined, TC will be in a better position to advise of the timeline necessary to implement the changes.
Following the receipt of TSB’s safety advisory letter, TC took the following actions:
- In early 2018, published guidance material concerning the use of safety belts in Aviation Safety Letter (ASL) issue 1/2018.
- In March 2018, published Civil Aviation Safety Alert (CASA) 2018-02, reminding operators of the correct use of passenger seatbelts and the importance of securing cargo.
Additionally, in November 2019, TC informally consulted with stakeholders at the Helicopter Association of Canada annual meeting on the potential impact of a definition change.
The Board is encouraged that TC has initiated work to address this safety deficiency. A change in the definition of “safety belt,” when fully implemented, will mitigate the risk associated with the safety deficiency identified in Recommendation A19-01.
Therefore, the Board considers the response to Recommendation A19-01 to show Satisfactory Intent.
Next TSB action
The TSB will monitor the progress of TC's planned actions to mitigate the risks associated with the safety deficiency identified in Recommendation A19-01, and will reassess the deficiency on an annual basis or when otherwise warranted.
This deficiency file is Active.
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