As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT ATTENDANTS REPORTED A DIRTY SOCK SMELL WHEN DESCENDING INTO DSM. WHEN ARRIVING AT GATE, TURNED ON APU BLEED AND GOT ACID SMELL IN THE FLIGHT DECK FOLLOWED BY A DIRTY SOCK SMELL IN ENTIRE CABIN. TURNED OFF APU BLEED AND ODOR SUBSIDED. REPLACED APU COOLING FAN IAW AMM 49-522-51-0401, OPS & LEAK CHECKED GOOD. REPLACED BOTH O-RINGS ON APU OIL RETURN LINE FROM OIL COOLER TO GEARBOX.