AD 76-01-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT4A-10 | PRATT & WHITNEY AIRCRAFT Model JT4A Engines |
| engine | Pratt & Whitney Division | JT4A-11 | PRATT & WHITNEY AIRCRAFT Model JT4A Engines |
| engine | Pratt & Whitney Division | JT4A-12 | PRATT & WHITNEY AIRCRAFT Model JT4A Engines |
| engine | Pratt & Whitney Division | JT4A-3 | PRATT & WHITNEY AIRCRAFT Model JT4A Engines |
| engine | Pratt & Whitney Division | JT4A-5 | PRATT & WHITNEY AIRCRAFT Model JT4A Engines |
| engine | Pratt & Whitney Division | JT4A-9 | PRATT & WHITNEY AIRCRAFT Model JT4A Engines |
Unsafe Condition
Tenth stage compressor blade failure resulting in case penetration.
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Required Actions
Shotpeen the tenth stage compressor blades in accordance with JT4A Overhaul Manual, P/N 384887, Section 72-36-1, and apply antigalling compound as per TR 72-617 of the same manual. Compliance must follow specified intervals based on time in service since last shotpeening or January 28, 1976.
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Compliance Time
Within 4000 hours time in service since last shotpeening to 6A intensity or within 2000 hours time in service since January 28, 1976, whichever is later, and every 4000 hours thereafter. For blades shotpeened to 11A intensity: within 6000 hours since last shotpeening or 2000 hours after January 28, 1976, whichever is later, and every 6000 hours thereafter. Blades never shotpeened must comply within 2000 hours after January 28, 1976, then follow paragraphs 1 and 2 intervals.
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Affected Aircraft
Pratt & Whitney Aircraft Model JT4A engines with tenth stage compressor blades P/N 499710 or P/N 310010.
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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