Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Turbomeca Arrius 1A and series turboshaft engines. This proposal would require installation of module TU63, which provides a separate supply of fuel for one of the 10 main injectors of the fuel injection system. This proposal is prompted by reports of unexpected power loss during test flights. The actions specified by the proposed AD are intended to prevent unexpected power loss, which could result in an uncommanded in-flight engine shutdown, autorotation, and forced landing.