Airworthiness Directives; Rolls-Royce Corporation (Type Certificate Previously Held by Allison Engine Company) Turboprop Engines

The FAA is adopting a new airworthiness directive (AD) for all Rolls-Royce Corporation (RRC) AE 2100A, AE 2100D2, AE 2100D2A, and AE 2100P model turboprop engines. This AD was prompted by a report of a propeller gearbox (PGB) development test conducted by the manufacturer, in which high vibration occurred due to a fatigue crack that initiated in the PGB shaft and carrier assembly. This AD requires assignment of usage hours to the PGB shaft and carrier assembly at the next engine shop visit and replacement of PGB shaft and carrier assemblies prior to exceeding the new life limits established by the manufacturer. The FAA is issuing this AD to address the unsafe condition on these products.