Summary
We propose to adopt a new airworthiness directive (AD) for certain Turbomeca S.A. Arriel 1E2 turboshaft engines. This proposed AD was prompted by reports of uncommanded in-flight shutdowns (IFSDs). This proposed AD would require removing the tachometer box on affected engines. We are proposing this AD to prevent failure of the tachometer box, which could lead to failure of the engine, IFSD, and loss of control of the helicopter.