AD 66-19-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-58A | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58B | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58BT | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58C | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58D | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58DT | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58E | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58ET | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58F | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-58FT | Airworthiness Directives; Sikorsky Models S-58 and S-61 Series Helicopters |
Unsafe Condition
Tail rotor blades with flex shank area of the spar having less than minimum hardness requirements.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect S 1615-30100, S 6115-30001, and S 6117-30001 series tail rotor blades as per Sikorsky Service Bulletin 58B15-6A or 61B15-5A. Remove from service blades not meeting minimum hardness requirements before further flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 50 hours' time in service after the effective date of this AD unless already accomplished
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Models S-58 and S-61 Series Helicopters equipped with tail rotor blades with serial numbers listed in Sikorsky Service Bulletin 58B15-6A or 61B15-5A.
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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