AD 89-04-01 R3
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-61N | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61N and S-61NM Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61NM | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61N and S-61NM Helicopters |
Unsafe Condition
Fracture of the sponson truss assembly components due to insufficient hardness of welded lugs.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Conduct hardness tests on welded lugs of specified sponson truss tube assemblies within 100 hours' time in service after the effective date. Inspect for cracks at intervals not exceeding 500 landings and remove components from service by June 30, 1989, if hardness is out of the C39 to C43 range. Replace components with hardness below C34 before further flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 100 hours' time in service after the effective date of this AD, and subsequent inspections at intervals not to exceed 500 landings.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Model S-61N and S-61NM helicopters, certificated in any category.
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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