Airworthiness Directives; Rolls-Royce Corporation AE 2100D2, AE 2100D2A, AE 2100D3, and AE 2100J Turboprop Engines

The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce Corporation (RRC) AE 2100D2, AE 2100D2A, AE 2100D3, and AE 2100J turboprop engines with certain propeller gearbox (PGB) shaft-and- carrier assemblies installed. These engines are U.S. type-certificated but as of the effective date of this AD are only installed on military airplanes. This AD requires monitoring a certain population of PGB shaft-and-carrier assemblies for vibration during flight, and borescope-inspecting the PGB shaft for cracks if vibration is experienced. This AD would also require removing the affected population of PGB shaft-and-carrier assemblies from service and installing serviceable PGB shaft-and-carrier assemblies. This AD results from a report of a crack found in the forward cone of a PGB shaft in an RRC AE 2100D3 turboprop engine that was removed from service due to high vibration. We are issuing this AD to prevent separation of the propeller from the airplane, which could result in injury, and damage to the airplane.