AD 78-09-09
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Rolls-Royce Corporation | 501-D13 | DETROIT DIESEL ALLISON Model 501-D13/501-D13A/501- D13D/501-D13E, and 501-D13H Engines |
| engine | Rolls-Royce Corporation | 501-D13A | DETROIT DIESEL ALLISON Model 501-D13/501-D13A/501- D13D/501-D13E, and 501-D13H Engines |
| engine | Rolls-Royce Corporation | 501-D13D | DETROIT DIESEL ALLISON Model 501-D13/501-D13A/501- D13D/501-D13E, and 501-D13H Engines |
| engine | Rolls-Royce Corporation | 501-D13E | DETROIT DIESEL ALLISON Model 501-D13/501-D13A/501- D13D/501-D13E, and 501-D13H Engines |
| engine | Rolls-Royce Corporation | 501-D13H | DETROIT DIESEL ALLISON Model 501-D13/501-D13A/501- D13D/501-D13E, and 501-D13H Engines |
Unsafe Condition
Third or fourth stage turbine wheel failure resulting from unknown carbide precipitation classifications or exceeding specified maximum life limits.
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Required Actions
Remove and classify third and fourth stage turbine wheels with unknown carbide precipitation classifications according to compliance times. Wheels classified as 'Heavy' must be removed from service if exceeding 8000 total cycles or prior to reaching specified limits. 'Medium Heavy' classifications require removal based on cycle ranges as outlined in the directive.
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Compliance Time
Compliance required within specified cycles as per the wheel's classification and cycle count on the effective date (May 12, 1978).
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Affected Aircraft
Rolls-Royce Corporation engines models 501-D13, 501-D13A, 501-D13D, 501-D13E, and 501-D13H equipped with specific turbine wheel part numbers installed in aircraft certificated in all categories.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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