AD 90-12-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Canada Corp. | PT6A-15AG | PRATT & WHITNEY CANADA PT6A series turbopropeller engines repaired by Gregory Flying Service/Airforce Turbine Service. |
| engine | Pratt & Whitney Canada Corp. | PT6A-27 | PRATT & WHITNEY CANADA PT6A series turbopropeller engines repaired by Gregory Flying Service/Airforce Turbine Service. |
| engine | Pratt & Whitney Canada Corp. | PT6A-28 | PRATT & WHITNEY CANADA PT6A series turbopropeller engines repaired by Gregory Flying Service/Airforce Turbine Service. |
| engine | Pratt & Whitney Canada Corp. | PT6A-29 | PRATT & WHITNEY CANADA PT6A series turbopropeller engines repaired by Gregory Flying Service/Airforce Turbine Service. |
| engine | Pratt & Whitney Canada Corp. | PT6A-34 | PRATT & WHITNEY CANADA PT6A series turbopropeller engines repaired by Gregory Flying Service/Airforce Turbine Service. |
| engine | Pratt & Whitney Canada Corp. | PT6A-34AG | PRATT & WHITNEY CANADA PT6A series turbopropeller engines repaired by Gregory Flying Service/Airforce Turbine Service. |
Unsafe Condition
The development of an unsafe condition which could result in an uncontained engine failure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove the engines from service within 30 calendar days after the effective date. Return to service requires either a complete engine overhaul per PWC manual or submission of records for FAA approval including life-limited components' service history, inspection records, FAA-approved data compliance evidence, test data, and accident involvement lists.
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Compliance Time
within the next 30 calendar days after the effective date of this AD
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Affected Aircraft
Pratt & Whitney Canada PT6A series engines with specific models and serial numbers repaired by Gregory Flying Service/Airforce Turbine Service in Tynan, Texas.
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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