AD 87-15-11
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-61A | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61L, S- 61N, S-61NM, S-61R, S-61A and S-61V Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61L | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61L, S- 61N, S-61NM, S-61R, S-61A and S-61V Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61N | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61L, S- 61N, S-61NM, S-61R, S-61A and S-61V Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61NM | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61L, S- 61N, S-61NM, S-61R, S-61A and S-61V Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61R | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61L, S- 61N, S-61NM, S-61R, S-61A and S-61V Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61V | Airworthiness Directives; SIKORSKY AIRCRAFT Model S-61L, S- 61N, S-61NM, S-61R, S-61A and S-61V Series Helicopters |
Unsafe Condition
Fatigue failure of the main gearbox servo support bracket (P/N's S6135-20248-0 and -2) or bracket assembly (P/N's S6135-20249-0 and -1).
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace the servo support brackets or assemblies with serviceable parts within specified time intervals. For S-61A, S-61L, S-61N, S-61NM, and S-61V models: within next 25 hours time in service after AD effective date or before 23,200 hours on the component, whichever is later. Thereafter, every 23,200 hours. For S-61R: within 25 hours or before 6,200 hours on the component, whichever is later. Thereafter, every 6,200 hours. Use rotorcraft hours if component records are unavailable.
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 of this AD or before the accumulation of [23,200 or 6,200 hours time in service on the bracket or assembly], whichever occurs later. Thereafter, replace at intervals not to exceed [23,200 or 6,200 hours time in service].
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Corporation Models S-61L, S-61N, S-61NM, S-61R, S-61A, and S-61V helicopters equipped with main gearbox servo cylinder support brackets (P/N's S6135-20248-0 and -2) or bracket assemblies (P/N's S6135-20249-0 and -1).
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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