As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DIRTY WET SOCKS PREVALENT FROM TAKEOFF THROUGH MID CLIMB, ODOR BECOMES VERY STRONG DURING DESCENT BELOW 5,000. APU FOUND TO BE SOURCE OF CABIN ODOR. MAINTENANCE ACCOMPLISHED JOBCARD 26L00021002 AND FOUND OIL COOLER LEAKING EXTERNALLY. MAINTENANCE ALSO REPLACED APU OIL COOLER AND PERFORMED SATISFACTORY OPERATIONAL CHECK PER AMM 49-91-44.