AD NUMBER: 2007-11-05
SUBJECT: Airworthiness Directive 2007-11-05
SUMMARY: This amendment adopts a new airworthiness
directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model
S-76A, B, and C helicopters.
This action requires a one-time ultrasonic inspection of the
main rotor shaft assembly (M/R shaft) for cracking.
This amendment is prompted by the discovery of cracking that
occurred during the manufacturing of certain M/R shafts.
The actions specified in this AD are intended to detect cracking
in the M/R shaft, which could result in separation of the main
rotor and subsequent loss of control of the helicopter.