Airworthiness Directives; Leonardo S.p.a. Helicopters

The FAA is adopting a new airworthiness directive (AD) for certain Leonardo S.p.a. Model A109E helicopters. This AD was prompted by reports that certain tail rotor gearbox assemblies were installed on Model A109E helicopters and those parts are not approved for installation on that helicopter model. Because those assemblies are not part of the type design for Model A109E helicopters, there are no overhaul or life limits included in the applicable maintenance manuals. This AD requires replacement of each affected tail rotor gearbox assembly with a serviceable part, 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.