Summary
We propose to adopt a new airworthiness directive (AD) for certain Turbomeca S.A. Arriel 1A1, 1A2, 1B, 1C, 1C1, 1C2, 1D, 1D1, 1E2, 1K1, 1S, and 1S1 turboshaft engines. This proposed AD was prompted by a ``chip illumination event'' in flight on a Turbomeca S.A. Arriel 1 engine. This proposed AD would require a one-time inspection of the free turbine (FT) module (M04) for the affected Turbomeca S.A. Arriel 1 engines and, if a discrepancy is found, repair of the affected module. We are proposing this AD to prevent a loss of FT bearing lubrication, resulting FT module failure, damage to the engine, and damage to the aircraft.