AD 74-25-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-61L | Airworthiness Directives; Sikorsky Models S-61L, S-61N, S-61NM and S-61R Helicopters Including Military CH-3C |
| aircraft | Sikorsky Aircraft Corporation | S-61N | Airworthiness Directives; Sikorsky Models S-61L, S-61N, S-61NM and S-61R Helicopters Including Military CH-3C |
| aircraft | Sikorsky Aircraft Corporation | S-61NM | Airworthiness Directives; Sikorsky Models S-61L, S-61N, S-61NM and S-61R Helicopters Including Military CH-3C |
| aircraft | Sikorsky Aircraft Corporation | S-61R | Airworthiness Directives; Sikorsky Models S-61L, S-61N, S-61NM and S-61R Helicopters Including Military CH-3C |
Unsafe Condition
The main rotor blades may have pockets that could fail due to fatigue cracking, leading to blade separation and loss of control.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Reduce maximum never exceed speed to 110 knots and install placards near airspeed indicators stating 'Never exceed speed 110 knots'.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 5 hours time in service after the effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Models S-61L, S-61N, S-61NM, S-61R helicopters including Military CH-3C with main rotor blades series S6115-20501, S6115-20601, S6117-20101, S6188-15001 except blades with serial numbers subsequent to 61M-6350-6105 or replaced by Sikorsky after October 30, 1972.
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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