What was found
BYPASS VALVE REMOVED TO COMPLY WITH LYCOMING SB 518A. THE NUT WAS FOUND LOOSE AND HALF-WAY UNSCREWED FROM THE THREADED SHAFT OF THE VALVE. IT WAS NOTED THE SERIAL NUMBER OF VALVE WAS HIGHER THAN THE AFFECTED SERIAL NUMBERS LISTED IN SB. RECOMMEND INSPECTION PER SB OF ALL VALVES REGARDLESS OF SERIAL NUMBERS. SB SHOULD BE AMENDED OR AN AD ISSUED.