AD 82-06-51
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-76A | Airworthiness Directives; SIKORSKY Model S-76A Series Helicopters |
Unsafe Condition
Failure of a main gearbox shaft and spur pinion P/N 76351-09012-103 due to fatigue cracks propagating in the bottom threaded area.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect shaft and spur pinions according to Sikorsky Alert Service Bulletin No. 76-66-16A or equivalent, replace cracked parts before further flight, and replace parts with serviceable ones based on time-in-service thresholds (1,500 hours since new or within 200 hours after AD effective date).
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within specified time windows: 50 hours' time in service for initial inspections of high-time parts, 100 hours' time in service for others, and replacement within 200 hours' time after AD effective date or 1,500 hours' time since new, whichever is later.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Model S-76A series helicopters with main gearbox assemblies P/N 76351-09000-061 or prior dash numbers.
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
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