Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Helicopters

摘要

We are adopting a new airworthiness directive (AD) for Sikorsky Model S-76A, B, and C helicopters to require certain inspections of each spindle cuff assembly or blade fold cuff assembly for a crack. If there is a crack, this AD requires replacing the cracked part. If there is no crack, this AD requires applying white paint to the inspection area to enhance the existing inspection procedure. This AD was prompted by discovery of cracks in the spindle cuffs. The actions are intended to prevent failure of a spindle cuff assembly or blade fold cuff assembly, loss of a rotor blade, and subsequent loss of control of the helicopter.