Airworthiness Directive · Amendment 39-12913 · Sikorsky Aircraft Corporation Model S-76A, S-76B and S-76C Helicopters
Sikorsky Aircraft Corporation Model S-76A, S-76B and S-76C Helicopters
Model S-76A, S-76B and S-76C helicopters, except those having a serial number of 760501, or 760506 through 760515, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for the specified Sikorsky Aircraft Corporation (Sikorsky) model helicopters that requires removing and inspecting each main rotor spindle attachment bolt (bolt) to ensure that the correct bolts are installed. This amendment is prompted by the discovery of improper bolts installed on a helicopter during its production. The actions specified by this AD are intended to detect installation of incorrect bolts, which could result in reduced hub or bolt fatigue life, separation of the main rotor blade at the spindle attachment, and subsequent loss of control of the helicopter.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
