Airworthiness Directives; Leonardo S.p.a. Helicopters

The FAA is adopting a new airworthiness directive (AD) for all Leonardo S.p.a. Model AB139 and AW139 helicopters. This AD was prompted by a report of a damaged tail rotor duplex bearing (TRDB). This AD requires repetitively inspecting certain TRDBs and depending on the results, replacing the TRDB or tail rotor actuator (TRA), or as an option, replacing the sliding control assembly. This AD also requires replacing an affected TRDB with a serviceable TRDB at a specified threshold and prohibits the installation of certain TRDBs or sliding control assemblies on any helicopter, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.