AD 79-20-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Honeywell International Inc. | LTP 101-600 | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
| engine | Honeywell International Inc. | LTP 101-600A | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
| engine | Honeywell International Inc. | LTP 101-600A-1A | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
| engine | Honeywell International Inc. | LTS101-600A | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
| engine | Honeywell International Inc. | LTS101-600A-2 | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
| engine | Honeywell International Inc. | LTS101-600B | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
| engine | Honeywell International Inc. | LTS101-650A-2 | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
| engine | Honeywell International Inc. | LTS101-650B-1A | AVCO LYCOMING DIVISION Model LTS101-600A, -600B, -600A-2, -650A-2, and -650B-1A and LTP101-600, -600A, and -600A-1A Engines |
Unsafe Condition
Failure of the fuel control and fuel pump and oil pump drive gears due to insufficient strength of the gears (P/N 4-081-080-04, 4-083-020-01, and 4-081-080-02).
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Required Actions
Remove and replace fuel control and fuel pump drive gears with P/N 4-083-020-02 for LTP101 engines and P/N 4-081-080-05 for LTS101 engines. Replace oil pump drive gears with P/N 4-081-080-06 for LTP101 engines.
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Compliance Time
prior to further flight
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Affected Aircraft
AVCO LYCOMING DIVISION LTS101-600A, -600B, -600A-2, -650A-2, -650B-1A turboshaft engines and LTP101-600, -600A, -600A-1A turboprop engines.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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