Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, B, and C Helicopters

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-17-15 which was sent previously to all known U.S. owners and operators of Sikorsky Aircraft Corporation Model S-76A, B, and C helicopters by individual letters. This AD requires, before further flight, a one-time visual inspection of the swashplate assembly uniball bearing retainer (retainer) for missing bolts, an inspection with a magnet to detect aluminum bolts, and replacing missing or aluminum bolts with airworthy steel bolts. This amendment is prompted by reports of the installation of aluminum bolts on swashplate assemblies. This condition, if not corrected, could result in failure of the swashplate assembly, loss of the main rotor, and subsequent loss of control of the helicopter.