AD 73-26-07 R3
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Honeywell International Inc. | TPE331-1 | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-1U | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-1UA | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-2 | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-25A | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-25AA | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-25AB | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-25B | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-25C | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
| engine | Honeywell International Inc. | TPE331-25D | AIRESEARCH MANUFACTURING COMPANY OF ARIZONA Model TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series Engines |
Unsafe Condition
Abnormal wear of the fuel pump shaft internal drive splines and coupling shaft external splines exceeding specified limits could result in fuel pump failure, leading to engine power loss.
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Required Actions
Inspect, clean, and lubricate fuel pump and coupling shaft drive splines per AiResearch Service Bulletin. Replace shafts if wear exceeds 0.003 inch or 0.005 inch as specified. Install new P/N 869911-3 couplings when replacing components. Discontinue inspections after incorporating improved alignment features per specified service bulletins.
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Compliance Time
Within the next 25 hours additional time in service or prior to exceeding specified service limits (200, 775, or 375 hours), and at intervals not exceeding 800 or 400 hours time in service thereafter.
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Affected Aircraft
Honeywell International Inc. TPE331-1, -2, -3, -5, -6, -25, -29, -43, -45, -47, -51, -55, -57, -61, and TSE331-3 Series engines with grease lubricated fuel pump drive coupling spline configuration.
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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