AD 84-11-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-61A | Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61L | Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-61N | Airworthiness Directives; SIKORSKY AIRCRAFT DIVISION Model S-61 L/N/A Series Helicopters |
Unsafe Condition
Flange failure due to cracks in flanges (Part Numbers S6135-66228-0, S6135-64013-0, S6135-66657-0) surrounding bolt attachments.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect flanges with over 800 hours time in service for cracks using a 5-power magnifying glass within 15 hours time in service after AD effective date. If cracks found, replace flange and ensure proper alignment of intermediate gearbox, tail gearbox, and pylon drive shaft before further flight. Allow equivalent methods or interval adjustments upon FAA approval with substantiating data.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 15 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 Model S-61 L/N/A series helicopters with flanges P/N S6135-66228-0, S6135-64013-0, or S6135-66657-0 in the tail rotor drive system.
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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