Part failure in the main rotor blade assembly resulted in 2021 fatal helicopter in-flight breakup near Evansburg, Alberta
Edmonton, Alberta, 7 September 2022 — In its investigation report (A21W0045) released today, the Transportation Safety Board of Canada (TSB) found that the failure of a main rotor blade hub strap retaining pin resulted in the occurrence helicopter’s in-flight breakup.
On 28 June 2021, at approximately 18:00 MDT, a Yellowhead Helicopters Ltd. Bell Textron Inc. model 212 helicopter was conducting operations in support of forest fire fighting efforts near Evansburg, Alberta. The helicopter was approaching the landing area to pick up a group of firefighters when one of the main rotor blades separated from the rotor head assembly. The second rotor blade and rotor head assembly then broke free from the helicopter and the helicopter crashed. The pilot, the sole occupant on board, was fatally injured. There was a post-impact fire that destroyed the helicopter.
The investigation determined that one of the main rotor hub strap retaining pins—a flight safety–critical aircraft part—was manufactured from a type of steel that was weaker than the steel required by design. As a result, the pin failed in flight and the associated main rotor blade separated from the helicopter. For undetermined reasons, the quality control systems in place at the pin’s manufacturer did not identify the non-conforming main rotor hub strap retaining pins; consequently, the pins were not removed from the supply chain.
After the occurrence, Bell Textron Inc. issued four alert service bulletins requiring the review of the aircraft’s technical record to determine if any non-conforming main rotor hub strap retaining pins were installed on model 204B, 205, 205B, and 212 helicopter fleets. If non-conforming pins were installed, they were to be replaced with conforming pins. Transport Canada issued an emergency airworthiness directive (CF-2021-23) mandating compliance with the Bell Textron Inc. alert service bulletins, as did the U.S. Federal Aviation Administration and the European Aviation Safety Administration.
See the investigation page for more information.
The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.
For more information, contact:
Transportation Safety Board of Canada