Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters

摘要

This document proposes adopting a new airworthiness directive (AD) for Sikorsky Model S-92A helicopters. This proposal would require revising the airworthiness limitations section of the Instructions for Continued Airworthiness (ICA) to reduce the life limit of the main gearbox housing and replacing any main gearbox housing that exceeds the life limit. This proposal is prompted by a fatigue analysis conducted after a helicopter was found with a severed main gearbox mounting foot pad (foot pad) that failed due to fatigue. The actions specified by this proposed AD are intended to prevent failure of the main gearbox mounting housing foot pad, loss of the main gearbox, and subsequent loss of control of the helicopter.