Action
Final rule.
Summary
The FAA is superseding airworthiness directive (AD) 2021-26- 08, which applied to certain Bell Textron Canada Limited Model 206, 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters. AD 2021-26-08 required removing certain nuts from service; installing newly designed nuts; applying a specific torque, and a torque stripe to each newly installed nut; after the installation of each newly designed nut, inspecting the torque; and depending on the inspection results, either applying a torque stripe, or performing further inspections and removing certain parts from service. AD 2021- 26-08 also prohibited installing any affected nut on any tail rotor drive shaft (TRDS) disc pack (Thomas) coupling. Since the FAA issued AD 2021-26-08, the FAA determined certain torque values and part numbers (P/Ns) need to be revised. This AD was prompted by reports of cracked or missing nuts installed on the TRDS Thomas couplings and the need to revise certain torque values and P/Ns in AD 2021-26-08. This AD requires removing certain nuts from service; installing newly designed nuts; applying torque and a torque stripe; and additional corrective actions if necessary. This AD also prohibits installing any affected nut on any TRDS Thomas coupling, as specified in a Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.