On August 18, 2023, the Federal Aviation Administration (FAA) issued
Emergency Airworthiness Directive (AD) 2023-17-51 for all Bell Textron Canada Limited Model 407 helicopters. This AD was prompted by a report of a disbonded area in a tail rotor (T/R) blade due to missing adhesive between the upper skin and core. This condition, if not addressed, could result in severe vibration, failure of the T/R blade, and subsequent loss of T/R control.
An investigation by Bell Textron Canada Limited identified 43 T/R blades that could be affected due to an error in the manufacturing process. On August 14, 2023, the company issued
Bell Alert Service Bulletin (ASB) 407-23-132 which identifies affected T/R blade serial numbers, specifies inspection procedures and directs T/R replacement as required. On August 17, 2023, Transport Canada issued
Emergency AD CF-2023-63 which mandates compliance with the above ASB for certain serial numbered aircraft within 10 flight hours or 14 days, whichever occurs first.
The FAA’s AD incorporates the entirety of the Transport Canada AD by reference with two changes. First, the FAA’s AD applies to all Model 407 helicopters. Second, the FAA’s AD specifically requires tap inspecting each affected T/R blade for skin to core voids.