What was found
(CAN) AIRCRAFT WAS DECLARED AOG DUE TO AN IN FLIGHT FUEL TRANSFER RESULTING IN AN IMBALANCE OF 200 KG. RT MOTIVE FLOW CHECK VALVE REMOVED, INSPECTED, AND FOUND ONE RIVET LOOSE WHICH AFFECTS THE FLAPPER TO SEAT IN ITS CORRECT POSITION. NEW VALVE INSTALLED. (TC# 20180404022).