AD 71-02-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT4A-10 | PRATT & WHITNEY Model JT4A Series Engines |
| engine | Pratt & Whitney Division | JT4A-11 | PRATT & WHITNEY Model JT4A Series Engines |
| engine | Pratt & Whitney Division | JT4A-12 | PRATT & WHITNEY Model JT4A Series Engines |
| engine | Pratt & Whitney Division | JT4A-3 | PRATT & WHITNEY Model JT4A Series Engines |
| engine | Pratt & Whitney Division | JT4A-5 | PRATT & WHITNEY Model JT4A Series Engines |
| engine | Pratt & Whitney Division | JT4A-9 | PRATT & WHITNEY Model JT4A Series Engines |
Unsafe Condition
Twelfth stage compressor rotor disc failure as a result of suspected material deficiency.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace the suspect serial number twelfth stage compressor rotor disc within specified cycles: for discs with 5000 cycles or more, within 25 cycles after the AD's effective date; for those with fewer cycles, prior to reaching 5025 cycles. Adjustments may be made with substantiating data through an FAA inspector.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 25 cycles in service after the effective date of this AD (May 4, 1971) for discs with 5000 cycles or more; prior to accumulation of 5025 cycles in service for those with fewer cycles.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt & Whitney JT4A series engines with specific 12th stage compressor rotor disc serial numbers listed in the AD (e.g., 1F-6145, 3F-8849, etc.).
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
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.