What was found
FUEL ODOR IN CABIN WITH APU DEBRIEFED CREW, FUEL ODOR DURING APU BLEED ON. SMELLED ODOR IN FLIGHT DECK FOR A FEW MINS. PARAMETER WERE NORMAL. TALKED TO FA, FA DID NOT SMELL ANY ODOR. .INSPECTED APU COMPARTMENT. FOUND FUEL BACKED UP IN AFT DRAIN LINE. SUSPECTED CLOGGED AT AFT DRAIN MAST, CLEARED DRAIN MASK AND LEAKED CHECK. NO LEAKS NOTED. APU OPS TEST NORMAL, NO SMELL. REF TSM 05-50-00-810-831-A AND AMM 49-17-00-200-805-A.