AD 79-18-13
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Rolls-Royce Corporation | 250-C28B | DETROIT DIESEL ALLISON Model 250-C28B and 250-C28C Series Engines |
| engine | Rolls-Royce Corporation | 250-C28C | DETROIT DIESEL ALLISON Model 250-C28B and 250-C28C Series Engines |
Unsafe Condition
Third stage turbine wheel blade failure due to use of turbine wheels with part numbers 6898553 or 6898773, which could cause engine power loss.
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Required Actions
Remove from service third stage turbine wheels with part numbers 6898553 or 6898773. Compliance is required before reaching 325 hours total time in service for wheels with less than 300 hours, or within 25 hours time in service for wheels with over 300 hours.
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Compliance Time
Before reaching 325 hours total time in service for turbine wheels with less than 300 hours total time in service; within 25 hours time in service for turbine wheels with more than 300 hours total time in service.
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Affected Aircraft
Rolls-Royce Corporation Model 250-C28B and 250-C28C engines equipped with third stage turbine wheel part numbers 6898553 or 6898773 installed in Bell 206L-1 rotorcraft.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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