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.
Within a few days of the accident, the TSB issued a safety advisory to raise awareness about the risks associated with unsecured cargo and unrestrained passengers in aircraft. During its investigation, the TSB found that the practice of carrying external loads attached to the platform, for flight to and from work sites, was not a formalized procedure at the company and, as a result, adequate controls were not in place to ensure that objects were properly stored or secured.
The investigation also found that 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. "The Canadian Aviation Regulations currently define a safety belt as "a personal restraint system consisting of either a lap strap or a lap strap combined with a shoulder harness,'" said Kathy Fox, Chair of the TSB. "Because of the word either, pilots and passengers may interpret the regulation to mean that use of the lap strap alone is sufficient. We want that uncertainty removed."
After the accident, Transport Canada published a safety letter that emphasized the importance of pilots wearing both the lap strap and the shoulder harness portion of the safety belt, whenever it is available. Hydro One Networks Inc. also took a number of corrective actions, such as suspending operations involving the external platform, completing a comprehensive review of its operations manual and procedures, and enhancing its training programs.
See the investigation page
