Airworthiness Directives; Turbomeca S.A. Arriel 1A1, 1A2, 1B, 1C, 1C1, 1C2, 1D, 1D1, 1E2, 1K1, 1S, and 1S1 Turboshaft Engines

This document publishes in the Federal Register an amendment adopting emergency airworthiness directive (AD) 2009-12-51 that was sent previously to all known U.S. owners and operators of Turbomeca S.A. Arriel 1A1, 1A2, 1B, 1C, 1C1, 1C2, 1D, 1D1, 1E2, 1K1, 1S, and 1S1 turboshaft engines. This AD requires initial and repetitive visual inspections of certain reduction gearboxes (module M05) for oil leakage, repair if leaking, and repair of all affected modules as terminating action to the repetitive inspections. This AD results from reports of oil leaks from certain reduction gearbox (module M05) front casings. The engine manufacturer reported that the lubrication duct plug was not properly bonded/glued in place. We are issuing this AD to prevent uncommanded in-flight engine shutdown, possible engine fire, and an emergency autorotation landing.