As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STRONG DIRTY SOCK SMELL + ODOR ONLY WHEN APU RUNNING ON GROUND.DISSIPATES WHEN APU SHUT DOWN. PERFORMED NO GO ODI PREVENTION STEPS PER WORK CARD 0550-2001 + EFIM SMELL OF SMOKE OR FUMES WITH APU AS SOURCE. PERFORMED DUCT BURNOUT + REPLACED BOTH RECERC FILTERS. NO FUMES NOTED. OK FOR SERVICE. REF TASK BD500-A-J21-22-03-01AAA-720A-A. (LP# 7902866)