AD 85-25-07 R1
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Rolls-Royce Corporation | 250-C28 | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C28B | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C28C | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C30 | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C30G | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C30G/2 | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C30M | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C30P | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C30R (T703-AD-700) | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
| engine | Rolls-Royce Corporation | 250-C30R/1 (T703-AD-700B) | ALLISON GAS TURBINE DIVISION, GENERAL MOTORS CORP. Model 250-C28 and -C30 Series Engines |
Unsafe Condition
Cracks at the butt or seam weld on outer combustion case assemblies P/N 6899237 or 23009569 could progress to a point where the case could rupture and cause an inflight sudden loss of power/shutdown.
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Required Actions
Inspect outer combustion case welds using visual and penetrant/soap solution methods at specified intervals. Replace/modify outer combustion case assemblies with P/Ns 23030910 or 23030911 depending on engine model and installation by specific deadlines.
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Compliance Time
Compliance is required as indicated unless already accomplished. Actions include inspections within specified time-in-service intervals and replacements by January 31, 1986, or June 30, 1986, depending on installation.
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Affected Aircraft
Allison Model 250-C28 and -C30 Series engines with outer combustion case assemblies P/N 6899237 or 23009569 installed in aircraft certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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