AD 93-25-05

final rule
Data completeness: 70%

ALLISON Model 250-C20S Engines

AD Number
93-25-05
Status
final_rule
Effective Date
Product Category
engine
Docket
91-ANE-50
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
engine Rolls-Royce Corporation 250-C20S ALLISON Model 250-C20S Engines

Unsafe Condition

Bolt fretting and fatigue failure of the main engine driveshaft flex coupling bolts, bushings, and nuts could lead to driveshaft detachment and engine failure.

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Required Actions

Within 90 days after the effective date, inspect the main engine driveshaft and replace the driveshaft flex coupling bolts, bushings, and nuts per Soloy Corporation Service Bulletin No. 04-780. Replace driveshafts with elongated bolt holes with serviceable parts.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within 90 days after the effective date of this AD

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Affected Aircraft

Allison Model 250-C20S engines modified by Soloy Conversion, Ltd. STC SE2352NM, installed on but not limited to Cessna 206 and 207 airplanes.

AI-generated summary from the source AD text. Verify against the official source before acting.

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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