As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. SMOKE IN CABIN ACCOUNT AUXILIARY POWER UNIT OIL INGESTION. APU PLENUM DRAIN AT APU AIR INLET BLOWING SMOKE WHICH IS BEING SUCKED INTO APU INLET. REMOVED AND REPLACED APU PER MCM CARD 49-96-83. ACCOMPLISHED PACK BURN PER MCM CARD 21-92-12. OPERATIONAL CHECK GOOD.