Airworthiness Directives; Sikorsky Aircraft-Manufactured Model S- 64F Helicopters

摘要

This amendment adopts a new airworthiness directive (AD), applicable to Sikorsky Aircraft-manufactured Model S-64F helicopters, that requires inspections, and replacement, if necessary, of the main gearbox second stage lower planetary plate (plate). This amendment is prompted by two incidents in which the plate was found cracked. The actions specified by this AD are intended to prevent failure of the plate due to fatigue cracking, which could lead to failure of the main gearbox and subsequent loss of control of the helicopter.