What was found
5AIRCRAFT WAS GROUNDED: MAINTENANCE REPORTS MUSTY SMELL IN COCKPIT AND CABIN WHEN PACKS WERE TURNED ON THROUGH APU. ALSO, ON DESENT INTO MCO F/A'S IN REAR OF ACFT SMELLED "DIRTY SOX SMELL" ENGINES WERE IDLE FOR DESENT. SEEM TO GET BETTER JUST PRIOR TO TOUCH DOWN. MAINTENANCE ACCOMPLISHED JOB CARD 26L00021001 "SMOKE ODOR FUMES INT. TROUBLESHOOTING". FOUND APU TO BE THE SOURCE OF CONTAMINATION. APU WAS FREE OF CONTAMINATES WITH EVIDENCE OF OIL LEAK IN PLENUM AREA .***SUPPLEMENTAL INFORMATION: MAINTENANCE REMOVED AND REPLACED APU IAW JOB CARD 26L31049003 LEAK AND OPS CHECKS GOOD.*** (CLOSED)