AD 71-06-03
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 either within the next 50 hours in service after the effective date if the disc has 18,000 hours or more in service, or prior to accumulating 18,050 hours in service if the disc has 18,000 hours or less in service. Substantiating data submission may allow compliance time adjustment.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 50 hours in service after the effective date of this AD (May 19, 1971) for discs with 18,000 hours or more in service, or prior to accumulating 18,050 hours in service for discs with 18,000 hours or less in service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt & Whitney Model JT4A series engines with 12th stage compressor rotor discs having serial numbers listed in the AD (e.g., 2G5181 to 2G6360, 5F7645 through 5F858, 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
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