AD 71-05-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Honeywell International Inc. | TPE331-1 | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-1U | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-1UA | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-2 | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-25A | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-25AA | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-25AB | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-25B | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-25C | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
| engine | Honeywell International Inc. | TPE331-25D | AIRESEARCH Model TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 Engines |
Unsafe Condition
Failure of the high speed pinion assembly
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Required Actions
Within 50 hours time in service after the effective date, perform a visual inspection of the engine oil filter per AiResearch Service Bulletin 628, Revision 2, and return oil and filter samples to AiResearch for examination. If excessive contamination is found, correct the cause before further flight. Revise AFM with a cautionary note about torque pressure fluctuations. Incorporate improved high speed pinion assembly at next engine overhaul per Service Bulletin 632 or 659.
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Compliance Time
Within 50 hours time in service after the effective date of this amendment to AD 71-05-07, as amended, and at intervals not to exceed 50 hours time in service thereafter
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Affected Aircraft
Honeywell International Inc. TPE331-1, -2, -25, -29, -43, -45, -47, -49, -51, -55, -57, -61 and -71 engines installed in Mitsubishi MU-2, Swearingen Merlin 2B, Volpar Turboliner, and Short Skyvan aircraft.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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