Service Bulletin No. 558

Inspection of Oil Suction Screen Area for Casting Voids


DATE: November 17, 2003


See attached list for engine models and serial numbers. Spares with part numbers 56A22634-01 and 56A22634-02 that were shipped from Lycoming between June 21, 2002 and April 17, 2003 are also affected by this Service Bulletin.


Next oil change or next 50-hour inspection.

Lycoming has determined that some oil sumps made from C56B19855 castings may have a casting void (hole) in the oil suction screen area (see Figure 1.) This casting void can result in a decrease in oil pressure during some maneuvers and/or low oil levels.

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