What was found
AIRCRAFT WAS GROUNDED: ODOR EVENT ON DESCENT THROUGH AND INCLUDING ON GROUND WHILE DOORS OPEN IN CMH MUSTY SMELL THROUGHOUT THE FLIGHT DECK AND CABIN. MAINTENANCE ISOLATED THE SOURCE OF THE ODOR TO THE APU AFTER FINDING OIL LEAKING FROM THE APU TURBINE COMPRESSOR DRAIN. **A SUPPLEMENTAL REPORT FOR AALA202309193177: MAINTENANCE REPLACED THE APU PER TAKS CARD 26L31049003 AND ACCOMPLISHED A SATISFACTORY LEAK / OPERATIONAL CHECK WITH NO ODORS NOTED.** (CLOSED)