As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING DESCENT FLIGHT CREW REPORTED A DIRTY / MUSTY SMELL AND SMELL DISAPPEARED WHEN THE #1 PACK WAS TURNED OFF. MAINTENANCE FOUND OIL LEAK AT THE APU OIL COOLING FAN AND APU OIL COOLER. REPLACED APU OIL COOLER PER AMM 49-91-44. (INITIAL REPORT AALA202108311356) ALSO REPLACED APU OIL COOLING FAN PER AMM 49-52-51.