Airworthiness Directives; Textron Lycoming IO-540, LTIO-540 and TIO-540 Series Reciprocating Engines

This amendment supersedes emergency airworthiness directive (AD) 2002-17-53 that was sent previously to all known U.S. owners and operators of Textron Lycoming LTIO-540 and TIO-540 series engines, rated at 300 horsepower (HP) or higher. That action requires, before further flight, replacing certain serial-numbered crankshafts that were hammer forged with crankshafts that were press forged. That AD was prompted by reports of crankshaft failures in LTIO-540 and TIO-540 engines, rated at 300 HP or higher. This amendment expands the suspect population of engines to include engines with crankshafts that were manufactured between March 1997 and the present and all IO-540 engines with crankshafts that were manufactured between March 1997 and the present that have been modified by supplemental type certificate (STC) by installing a turbocharger system. The actions specified by this AD are intended to prevent failure of the crankshaft, which could result in total engine power loss, in-flight engine failure and possible forced landing.