AD 74-10-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT9D-3A | PRATT & WHITNEY Models JT9D-3A and JT9D-7 Engines |
| engine | Pratt & Whitney Division | JT9D-7 | PRATT & WHITNEY Models JT9D-3A and JT9D-7 Engines |
Unsafe Condition
The possibility of internal main gearbox fires in the event of an internal gearbox failure and leakage of oil around carbon face seals.
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Required Actions
Rework the main gearbox per Service Bulletin No. 4043 and replace seal assemblies with redesigned carbon face seals per Service Bulletin No. 3902. Equivalent methods require approval from the Chief, Engineering and Manufacturing Branch, FAA.
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Compliance Time
not later than February 1, 1975
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Affected Aircraft
Pratt & Whitney Models JT9D-3A and JT9D-7 turbofan engines
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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