Primary finding
Probable cause
Improper engine overhaul and noncompliance with an airworthiness directive by other maintenance personnel.
Investigator assessment
Analysis narrative
An engine failed 37 operating hours after overhaul. The locating dowel for the crankshaft gear sheared after an incorrect part was used in place of the specified attaching bolt. The mechanic was unaware of an airworthiness directive applicable to the effected parts and their installation, and reused an apparently serviceable item. The inspector was aware of the directive, but interpreted it as inapplicable.
Source record
Factual narrative
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