AD 99-07-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-76C | Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-76C Helicopters |
Unsafe Condition
Failure of the engine Hydromechanical Unit (HMU) to deliver required fuel flow could result in inability to achieve published One-Engine-Inoperative (OEI) performance and subsequent loss of helicopter control.
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Required Actions
Insert new operating limitations and performance data into the Rotorcraft Flight Manual (RFM) SA 4047-76C-10, including RFM (Basic) Revision 7, Supplement No. 8 Revision 1, and Supplement No. 9 Revision 1, dated February 1, 1999, to require lower allowable gross weights for certain operational conditions.
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Compliance Time
before further flight
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Affected Aircraft
Sikorsky Model S-76C helicopters with Turbomeca Arriel 2S1 engines and HMU part numbers 0.292.92.822.0, 0.292.92.808.0, 0.292.92.813.0, or 0.292.92.828.0.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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