AD 91-24-13
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-76A | Airworthiness Directives; Sikorsky Aircraft Model S-76A Helicopters |
Unsafe Condition
Failure of the helicopter vertical pylon forward spar cap, web, and web doubler due to cracks in the areas adjacent to the tail rotor shaft cutout and fuselage shear deck.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect for cracks in the forward spar cap angles, spar web, and web doubler in the tail rotor shaft cutout and fuselage shear deck areas. Clean and visually inspect using a light and mirror, and replace or repair cracked parts as specified, including replacement prior to further flight if cracks exceed 2 1/2 inches or multiple cracks exist.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 25 hours' time in service after the effective date (December 20, 1991) for helicopters with 100+ hours' time in service, and before attaining 125 hours' time in service for those with less than 100 hours. Repeat inspections at intervals not exceeding 50 hours' time in service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Model S-76A helicopters equipped with forward spar cap angles (P/N 76201-05001-103/-104), forward spar web (P/N 76201-05001-101), and web doubler (P/N 76201-05001-107), not modified with Kit 76070-20086 per Alert Service Bulletin 76-55-12.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.