Summary
We propose to adopt 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 proposed AD would require replacing the cracked part. If there is no crack, this AD would require applying white paint to the inspection area to enhance the existing inspection procedure. This proposed AD is prompted by the discovery of cracks in the spindle cuffs. The proposed 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.