Bolt Confusion
The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.
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Some operators of aircraft with Lycoming -540 series engines who were hit by a pair of crankshaft bolt ADs last year got another letter from the FAA: Never mind.
The emergency AD and the superceding AD issued in December required owners of Lycomings big six-cylinder engines to replace the crankshaft gear retention bolt. The AD cut across applications, applying to aerobatic engines, turbos, left-turning engines and for airplanes and helicopters. Although it applied only to those engines with a Lycoming part number STD-2209 retaining bolt, many people didnt mak…