AD 74-15-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT3D-1 | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-1-MC6 | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-1-MC7 | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-1A | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-1A-MC6 | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-1A-MC7 | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-3 | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-3B | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-3C | PRATT & WHITNEY Model JT3D Engines |
| engine | Pratt & Whitney Division | JT3D-5A | PRATT & WHITNEY Model JT3D Engines |
Unsafe Condition
14th stage compressor discs, P/N 657814, may exceed cyclic life limits leading to disc failure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove from service 14th stage compressor discs prior to exceeding the revised life limits (JT3D-1: 10,000 cycles; JT3D-3B/JT3D-7: 8,000 cycles) or within 25 cycles after the effective date (July 25, 1974), whichever comes later. Discs used in multiple engine models must adhere to the lowest cycle life limit.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 25 cycles in service after the effective date of this airworthiness directive whichever comes later
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Affected Aircraft
Pratt & Whitney Model JT3D engines with 14th stage compressor disc P/N 657814, including models JT3D-1, JT3D-3B, and JT3D-7.
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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