The Dec. 14, 2017 accident that killed the pilot and all three technicians aboard an Airbus Helicopters AS350B2 was the result of a preform bag and its carabiner attached to an external platform separating from the platform and striking the helicopter's tail rotor, according to a Transportation Safety Board of Canada (TSB) final report. The Hydro One Networks-owned helicopter was conducting power line maintenance near Tweed, Ontario, and crashed during approach to landing
That strike caused significant damage, severe imbalance, and intense vibration that caused the tail rotor, tail rotor gearbox, and vertical fin to separate before the helicopter hit terrain.
“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,” the TSB said. It further noted that two of the three rear-seat passengers did not have their seatbelts fastened.
A week after the crash, the TSB issued a safety recommendation calling for all operators to ensure cargo is “adequately secured at all times, to prevent it from shifting or departing the helicopter during flight.” It also reminded operators that unbelted passengers “risk serious injury or death in the event of an emergency.” However, the TSB could not conclude that this crash would have been survivable to belted passengers.