As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB DIRTY SOCK (MELTED CRAYON) SMELL VERY PROMINENT IN CABIN AIR. INTENSITY INCREASED DURING CLIMB AND CRUISE AND CONTINUED DURING DESCENT. TROUBLESHOOTING DETERMINED THAT ODOR IS COMING FROM APU SUSPECT LOAD COMPRESSOR SEAL. WHILE PERFORMING FIM TASK 49 55 00 810 802 COMPRESSOR DISCHARGE DRAIN PLUG SHEARED OFF. REMOVED AND REPLACED APU REF MIG 2C NR 220223 AND T/C 78349010.