News item courtesy of Tom Turner. Although the piece is aimed at Beech Travel Air owners, many of you may want to know this as well. See Possible NPRM Affecting Lycoming Engines. ABS has learned that a Notice of Proposed Rulemaking affecting Lycoming IO-360 engines on Beech Travel Airs may be published as early as this week. A NPRM is the precursor to a mandatory Airworthiness Directive (AD).Identified problems with crankshafts on O-360 and IO-360 series engines, as well as O-540 and IO-540 engines of 300 horsepower and less, have resulted in Lycoming Mandatory Service Bulletin 566. This MSB calls for checking logbook or similar records for engines “manufactured, rebuilt, overhauled or repaired” after March 1, 1999 against a list of crankshaft serial numbers published in the Bulletin. Crankshafts with a serial number match should be replaced with a new crankshaft, according the Lycoming. Time for compliance is 50 operating hours or six months from the publication of MSB 566 (July 11, 2005), whichever comes first.

The Bulletin states, “Factory replacement of (affected) crankshafts…will be accomplished at no cost to the owner. Labor for engine removal and re-installation, when authorized (beforehand) by Lycoming, will be reimbursed in accordance with the current revision of the Removal and Installation Labor Allowance Guidebook, SSP-875 through an authorized Lycoming distributor, using the standard warranty procedure….Engines that have complied with Lycoming Service Bulletins 552 or 553 are not affected by this Bulletin.”

Should an AD be issued the provisions of Lycoming Mandatory Service Bulletin 566 will indeed be mandatory for these engines.

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