As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON DESCENT INTO SAN DIEGO -POWER AT IDLE VERY STRONG MUSTY ODOR FROM PACKS UNTILL ENGINE SHUTDOWN. MORE NOTICABLE IN FLIGHT DECK THAT THE CABIN. MAINTENANCE ISOLATED THE SOURCE OF THE ODOR TO THE APU. **SUPPLEMENTAL REPORT WILL BE SUBMITTED**(OPEN)