AD 91-14-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Honeywell International Inc. | ALF502L | AVCO LYCOMING Model ALF 502L Series Engines |
| engine | Honeywell International Inc. | ALF502L-2 | AVCO LYCOMING Model ALF 502L Series Engines |
| engine | Honeywell International Inc. | ALF502L-2A | AVCO LYCOMING Model ALF 502L Series Engines |
| engine | Honeywell International Inc. | ALF502L-2C | AVCO LYCOMING Model ALF 502L Series Engines |
| engine | Honeywell International Inc. | ALF502L-3 | AVCO LYCOMING Model ALF 502L Series Engines |
Unsafe Condition
Complete loss of engine power, uncontained disk failure, and possible damage to the aircraft due to corrosion pitting or cracks in the third stage high compressor rotor disks.
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Required Actions
Clean, visually inspect, coat with 'Sermetel W' or 'ALSEAL-518', and reidentify third stage high compressor rotor disks per Textron Lycoming Service Bulletin ALF 502L 72-203, Revision 3. Remove disks with corrosion pitting or cracks prior to further flight. Ferrying allowed under FAR 21.197/21.199.
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Compliance Time
Within the next 500 cycles in service, not to exceed 8,500 cycles since new (CSN) for disks at or above 7,000 CSN on AD effective date; or at or prior to 7,500 CSN for disks below 7,000 CSN on AD effective date.
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Affected Aircraft
Avco Lycoming ALF 502L series turbofan engines installed on, but not limited to, Canadair Challenger CL601 aircraft.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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