Safety communications related to TSB investigation A17O0264
On 14 December 2017, an Airbus AS 350 B2 helicopter owned by Hydro One Networks Inc. was transporting three power line technicians from a transmission tower to a staging area near Tweed, Ontario. During the descent, an empty canvas supply bag blew off from an external platform attached to the aircraft and, along with its carabiner, struck and severely damaged the tail rotor. Shortly after, the helicopter became uncontrollable and collided with terrain. All occupants were fatally injured.
Safety advisory issued on 21 December 2017
One week after the accident, the TSB issued Aviation Safety Advisory A17O0264-D1-A1 to alert organizations, raising awareness about the risks associated with unsecured cargo and unrestricted passengers with the following safety messages:
- Cargo must be adequately secured at all times, to prevent it from shifting or departing the helicopter during flight.
- Passengers who do not wear seat belts risk serious injury or death in the event of an emergency.
Recommendation made on 30 October 2019
As the investigation revealed, prior to the occurrence, the shoulder harness portions of the backseat safety belts were rolled up and taped with electrical tape, thereby preventing their use. There was a perception within the company that the use of the shoulder harness was optional as long as the lap strap was used.
Subsection 101.1(1) of the Canadian Aviation Regulations defines a safety belt as “a personal restraint system consisting of either a lap strap or a lap strap combined with a shoulder harness.” Based on this definition, many operators may consider that they are 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 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.
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.
Transport Canada 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 recommends 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
The Canadian Transportation Accident Investigation and Safety Board Act specifically provides for the Board to make recommendations to address systemic safety deficiencies posing significant risks to the transportation system and, therefore, warranting the attention of regulators and industry.
Under the Act, federal ministers must formally respond to TSB recommendations within 90 days and explain how they have addressed or will address the safety deficiencies.