Summary
This amendment proposes rescinding an existing Airworthiness Directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 407 helicopters. That AD currently requires, before further flight, imposing never exceed velocity (Vne) restrictions on the helicopter. The requirements of that AD were intended to prevent tail rotor blades from striking the tailboom, separation of the aft section of the tailboom with the tail rotor gearbox and vertical fin, and subsequent loss of control of the helicopter. That AD was prompted by an accident suspected of being the result of a tail rotor strike caused by high airspeed. Since the issuance of that AD, accident investigation findings have not substantiated that a tail rotor strike caused by high airspeed was the cause of the accident. This action would require rescinding that AD. This proposal is prompted by the FAA's determination that the Vne restrictions and accompanying actions imposed by that AD do not correct an unsafe condition.