Airworthiness Directive 2000-23-52
recurringAirworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, S-76B, and S-76C Helicopters
What this AD requires
This document publishes in the Federal Register an amendment adopting superseding Airworthiness Directive (AD) 2000-23-52, which was sent previously to all known U.S. owners and operators of Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, S-76B, and S-76C helicopters by individual letters. This AD requires, before further flight, performing a fluorescent penetrant inspection of the main rotor shaft assembly (shaft). Also required are recurring fluorescent penetrant inspections and visual inspections for any crack. If any crack is found, the shaft must be replaced with an airworthy shaft before further flight. This amendment is prompted by the discovery of two in-service cracked shafts, one with 477 hours time-in-service (TIS) and one with 313 hours TIS. A third shaft, that had been rejected from the manufacturing process for other reasons, was also discovered to have a crack. The actions specified by this AD are intended to prevent failure of the shaft and subsequent loss of control of the helicopter.
Which aircraft AD 2000-23-52 applies to
Cross-reference boilerplate only; model list precedes excerpt and was not captured. Requires a fluorescent-penetrant inspection of the shaft before further flight, a daily 10x-magnifier visual check, and a repetitive FPI every 20 hours TIS/80 landings (area above the upper shaft output seal, below the lower hub attachment flange), per Sikorsky Alert Service Bulletin No. 76-66-31, Revision B, dated November 7, 2000; cracked shafts replaced before further flight. Shafts P/N 76351-09030-series with serial-number prefix 'B' and numbers 015-00700 through 015-00706 must be removed from service before further flight.
Whether AD 2000-23-52 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.