Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for Turbomeca S.A. Arriel 2D turboshaft engines. This proposed AD was prompted by a low fuel pressure event caused by a deterioration and a loss of the low-pressure drive function within the hydro-mechanical metering unit (HMU). This proposed AD would require replacing the HMU at a reduced life. We are proposing this AD to prevent an uncommanded in-flight shutdown of the engine, and possible loss of the helicopter.