AD 78-23-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT8D-1 | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
| engine | Pratt & Whitney Division | JT8D-1A | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
| engine | Pratt & Whitney Division | JT8D-1B | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
| engine | Pratt & Whitney Division | JT8D-7 | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
| engine | Pratt & Whitney Division | JT8D-7A | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
| engine | Pratt & Whitney Division | JT8D-7B | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
| engine | Pratt & Whitney Division | JT8D-9 | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
| engine | Pratt & Whitney Division | JT8D-9A | PRATT & WHITNEY AIRCRAFT Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9 and -9A Engines |
Unsafe Condition
Third stage turbine blade rivet failure could result in failure of the low turbine shaft and/or noncontainment of turbine blade and vane debris.
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Required Actions
Inspect engines for proper position of the third stage turbine blade in the disk slot per JT8D Maintenance Manual or approved means. Re-inspect every 1,000 hours if no displacement over .032 inch. Install improved rivets (P/N 759351) by June 30, 1980.
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Compliance Time
Prior to the accumulation of 3,000 hours time in service since installed in disk or within the next 600 hours time in service after the effective date of this AD, whichever is later. Install improved rivets by June 30, 1980.
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Affected Aircraft
Pratt & Whitney Aircraft JT8D-1, -1A, -1B, -7, -7A, -7B, -9, and -9A engines not incorporating third stage turbine blade retention rivets P/N 759351 or P/N 618749.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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