*External bag, carabiner struck Hydro One tail rotor: TSB*
Canada’s Transportation Safety Board (TSB) has revealed more information about the Dec. 14, 2017, crash of a Hydro One AS350 B2 AStar near Tweed, Ontario.
The TSB said in a news conference on Dec. 21 that bags used for carrying tools and supplies were being transported externally on an AirStair platform extending from the right side of the helicopter’s fuselage.
Investigators noted these bags are normally attached to the AirStair with double-lock carabiners.
Shortly before the accident, the pilot picked up the three linemen at the base of a tower and was ferrying them to a nearby staging area. While nearing the staging area, one of the bags dislodged from the platform and, together with its attached carabiner, flew back and struck the tail rotor, which subsequently separated from the aircraft.
The helicopter departed controlled flight and all three passengers were ejected from the aircraft while it was still airborne. Investigators later found that two of the three passenger seatbelts in the aft seating area were unfastened.
Members of the TSB team also located a damaged white canvas bag (with a damaged carabiner attached) as well as the tip of a tail rotor blade more than 600 meters (1,968 feet) away from the crash site.