Airworthiness Directive 98-17-15
one-timeAirworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, B, and C Helicopters
What this AD requires
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.
Which aircraft AD 98-17-15 applies to
Main rotor swashplate assembly uniball bearing retainer; one-time inspection for missing/aluminum retainer bolts (12 installed), replace with airworthy AN3-5A steel bolts. Per Sikorsky SB 76-65-47.
Whether AD 98-17-15 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.