AD 99-01-09

final rule
Data completeness: 60%

Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76C Helicopters

AD Number
99-01-09
Status
final_rule
Effective Date
Product Category
aircraft
Docket
98-SW-81-AD

Applicability

TypeManufacturerModelDetails
aircraft Sikorsky Aircraft Corporation S-76C Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76C Helicopters

Unsafe Condition

Air getting into a fuel supply line when there is less than 250 lbs. of fuel in either fuel tank, leading to engine flame-out and a subsequent forced landing.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Before further flight, install a placard adjacent to the fuel quantity gauge stating 'No flight operations to be conducted with less than 250 lbs. fuel in each tank' and revise the Rotorcraft Flight Manual (RFM) by inserting this AD in the Operating Limitations section. Within 50 hours time-in-service or 30 calendar days, whichever occurs first, defuel both tanks until the #1 and #2 FUEL LOW warning lights illuminate, start engines in direct feed and crossfeed positions, monitor for engine start issues, and inspect fuel suction lines for unseated fittings, corrosion, or pitting, replacing or reinstalling components as necessary.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Before further flight and within 50 hours time-in-service or 30 calendar days, whichever occurs first.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Sikorsky Aircraft Corporation Model S-76C helicopters, serial numbers 760477, 760479, 760481 through 760487, 760490, 760491, and 760493, certificated in any category.

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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