AD 79-25-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-76A | Airworthiness Directives; Sikorsky Model S-76A Helicopters |
Unsafe Condition
Hydraulic pumps (Sikorsky P/Ns 76650-09802-101 and 102) may fail due to fluid loss causing dry running, leading to system malfunction.
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Required Actions
Replace defective pumps prior to further flight. Service and bleed systems if fluid loss occurs but system remains wet. Check hydraulic pressure during rotor startup and replace malfunctioning components. Replace all affected pumps with P/N 76650-09802-103 within specified timeframes based on hours in service.
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Compliance Time
Within the next 100 hours time in service for pumps with 250+ hours on effective date, or before accumulation of 350 hours time in service for those with less than 250 hours.
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Affected Aircraft
Sikorsky Model S-76A helicopters equipped with hydraulic pumps P/N 76650-09802-101 or 102.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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