As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: 5 MIN AFTER TAKEOFF FA'S REPORT FUME EVENT IN AFT AIRCRAFT SMELLOF RUBBER, SOCKS, AND BURNT PLASTIC STRONGEST IN THE BACK MOVING FORWARD. APU LOAD COMPRESSOR FOUND TO BE SOURCE. FOUND OIL LEAKING INTO INTAKE MANIFOLD FROM LOAD COMPRESSOR. REPLACED APU.