Service Bulletin No. 561

DATE: August 6, 2004

MODELS AFFECTED

Any Lycoming factory new or overhauled model (L)TIO-540-U2A, -V2AD, and -W2A engines listed on ATTACHMENT I.

Any (L)TIO-540-U2A, -V2AD or -W2A engines that have had genuine Lycoming P/N LW-13212 connecting rod bearing installed during field overhaul or field maintenance between August 25, 1995 and the date of this Service Bulletin.

TIME OF COMPLIANCE

Replace bearings as scheduled with an approved facility listed in ATTACHMENT II. Change oil at 10-hour intervals until new connecting rod bearings are installed.

Instances of a connecting rod bearing failure have occurred recently on (L)TIO-540-U2A engines. The failure results in a disintegration of the bearing most likely due to delamination of the bearing surface. Lycoming has found no apparent operational or dimensional cause for these occurrences; however, in an effort to minimize any chance of an additional occurrence, Lycoming is instituting a mandatory replacement program to equip the subject engines with connecting rod bearings with increased durability. The specific details concerning this program may be obtained from Lycoming Engines at (570)323-6181.