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Service Instruction No. 1517
DATE: October 27, 2006 MODELS AFFECTED Lycoming model TIO-540-AK1A aircraft engines. TIME OF COMPLIANCE At overhaul or at owner’s discretion. A slight increase in engine performance has been found by changing the engine timing from 20° BTC to 23° BTC. This modification has been incorporated in the current production of both new and rebuilt engines. This timing change does not affect the normal...