Summary
The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Turbomeca S.A. Arriel -1B, -1D, and -1D1 series turboshaft engines. This proposal would require replacement of modules M03 modified to TU 204 standard with modules M03 not modified to TU 204 standard. This proposal is prompted by several reports of 2nd stage gas generator turbine blade failures. The actions specified by the proposed AD are intended to prevent 2nd stage gas generator turbine blade failure resulting in uncommanded engine in-flight shutdown.