What was found
AIRCRAFT WAS GROUNDED: AFTER ENGINE START, AFT GALLEY FLIGHT ATTANDENT REPORTED A SWEET AND BURNING SMELL THAT QUICKLY DISSIPATED. A FEW MINUTES LATER, A STRONG GAS SMELL EMANATED FROM THE AFT PART OF THE AIRCRAFT. APU WAS OFF. FLIGHT DECK TRIED TO ISOLATE BLEEDS AND PACKS TO NO SUCCESS. VERIFIED APU SOURCE OF SOF. LEAK FOUND AT 6 OCLOCK POSITION (APU TURBINE SCAVENGE OIL RETURN TUBE).**SUPPLEMENTAL REPORT FOR (AALA202412020678): REMOVED AND REPLACED APU. PER JOB CARD # 08L30049001**(CLOSED).