As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: THE ENTIRE CABIN HAS A MUSTY ODOR WHEN THE PACKS ARE ON. ODOR IS WORST ON THE GROUND WHEN THE APU IS SUPPLYING AIR. MAINTENANCE ISOLATED SOURCE OF ODOR TO THE APU. **SUPPLEMENTAL REPORT FOR AALA202204270446: MAINTENANCE FOUND THE APU COOLING FAN LEAKING OIL AND REPLACED IT PER AMM 49-59-51. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED. .** (CLOSED)