Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Turbomeca Makila 1 series turboshaft engines. This proposal would require a one-time visual inspection of the scavenge and lubrication systems for obstruction due to coke deposits, then reconditioning of the engine oil system prior to return to service. This proposal is prompted by report of an in-flight engine shutdown due to roller bearings contaminated by certain types of detergent oil. The actions specified by the proposed AD are intended to prevent in-flight engine shutdown due to roller bearing failure following oil contamination.