Transport Canada is asking operators of a range of Bell medium helicopters equipped with Airwolf Aerospace Tension-Torsion (TT) straps to inspect them “at the earliest opportunity,” following the fatal crash of a Bell 212 on June 28 near Fort Good Hope Airport, Northwest Territories.
The call, issued in a Civil Aviation Safety Alert (CASA) July 18, impacts operators of Bell 204, 205, 206, 210, and 212 helicopters.
While the investigation into the Fort Good Hope crash is still in its early stages, investigators identified a failed Airwolf TT strap at the scene, and said the aircraft’s main rotor blade had separated from the head. Speaking to Vertical on July 4 about the accident, investigators confirmed the strap failed at the outboard pin position.
Canada’s Transportation Safety Board (TSB) quickly spread the information to operators in Canada and the United States, with many then temporarily grounding their aircraft to inspect the straps.
Following this, Transport Canada said it received a Service Difficulty Report (SDR) that an Airwolf TT strap from a Bell 206B had a crack in the urethane coating, exposing the wires underneath.
“Given the recent accident and the subsequent Bell 206B SDR submission, a detailed inspection is strongly recommended,” the CASA states.
It said defects such as strap bulge and cracks in the urethane coating are of particular interest. “The integrity of the urethane coating requires close attention, especially at each spool end of the strap,” the CASA notes. “This proactive approach can help identify the root cause of any failure modes that may be present.”
