AD 77-01-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT9D-20 | PRATT & WHITNEY AIRCRAFT Models JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 Engines |
| engine | Pratt & Whitney Division | JT9D-3A | PRATT & WHITNEY AIRCRAFT Models JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 Engines |
| engine | Pratt & Whitney Division | JT9D-7 | PRATT & WHITNEY AIRCRAFT Models JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 Engines |
| engine | Pratt & Whitney Division | JT9D-7A | PRATT & WHITNEY AIRCRAFT Models JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 Engines |
| engine | Pratt & Whitney Division | JT9D-7AH | PRATT & WHITNEY AIRCRAFT Models JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 Engines |
| engine | Pratt & Whitney Division | JT9D-7F | PRATT & WHITNEY AIRCRAFT Models JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 Engines |
| engine | Pratt & Whitney Division | JT9D-7H | PRATT & WHITNEY AIRCRAFT Models JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 Engines |
Unsafe Condition
Cracking and possible failure of fifth stage turbine hubs due to cyclic life limits exceeding approved figures.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove from service fifth stage turbine hubs prior to reaching the revised life limits (listed by part number) or within the next 25 cycles after the AD's effective date, whichever is later. Operators may request FAA approval to adjust the 25-cycle compliance interval with substantiating data.
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
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt & Whitney Aircraft JT9D-3A, -7, -7H, -7A, -7AH, -7F and -20 engines with fifth stage turbine hubs P/N 704705, 714905, 718905, 719205, and 726805.
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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