AD 64-11-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT4A-11 | PRATT & WHITNEY Models JT4A-3, -9 and -11 Engines |
| engine | Pratt & Whitney Division | JT4A-3 | PRATT & WHITNEY Models JT4A-3, -9 and -11 Engines |
| engine | Pratt & Whitney Division | JT4A-9 | PRATT & WHITNEY Models JT4A-3, -9 and -11 Engines |
Unsafe Condition
Front compressor failure as a result of front compressor rotor blade shift in front compressor rotor assemblies incorporating blade locks P/N's 429601, 310293, 429602, 310294, 429603, 310295, 429604, and 310296.
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Required Actions
Inspect all front compressor blades in the fifth through eighth stages for blade axial displacement using a boroscope or FAA-approved equivalent viewing instrument. If displacement exceeds specified limits (0.045-0.080 inch forward, 0.040-0.080 inch aft), reinspect within every 125 hours' time in service. If displacement is between 0.080-0.120 inch, remove engine within 25 hours' time in service. If over 0.120 inch, remove before further flight.
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Compliance Time
Compliance required as indicated.
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Affected Aircraft
Pratt & Whitney Models JT4A-3, -9, and -11 Turbojet Engines with front compressor rotor assemblies using blade locks P/N's 429601, 310293, 429602, 310294, 429603, 310295, 429604, and 310296.
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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