Summary
This document proposes adopting a new airworthiness directive (AD) for the specified Sikorsky Aircraft Corporation (Sikorsky) model helicopters. The AD would require installing a Number 5 bearing chip detector in each engine, installing an on-board chip detector annunciation system, and revising the Rotorcraft Flight Manual (RFM) to add procedures for crew response to an on-board chip detector annunciation. This proposal is prompted by reports of the failure of the engine's Number 5 bearing that resulted in erratic movement of the high-speed engine-to-transmission shaft (shaft), oil leakage, an in-flight fire and an emergency landing. The actions specified by the proposed AD are intended to detect an impending engine bearing (bearing) failure and prevent a bearing failure, oil leakage, severing of the shaft housing, an uncontained in-flight fire, and a subsequent immediate emergency landing.