As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AFTER TAKEOFF AND DURING INITIAL CLIMB FUMES WERE SMELLED IN FLIGHT DECK AND ALSO REPORTED IN CABIN BY FLIGHT ATTENDANT. SMELLED LIKE EXHAUST OR OIL. FLIGHT ATTENDANT SAID IT SMELLED LIKE BURNT CRAYONS / MUSTY. MAINTENANCE ISOLATED THE SOURCE OF THE ODOR TO THE APU DUE TO FINDING EVIDENCE OF OIL LEAKING FROM THE LOAD COMPRESSOR DRAIN. (OPEN)