As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: THROUGH 24000 FT. STRONG ACRID/SMOKE/BURNING OIL SMELL.FLIGHT ATTENDANT NOTICED SAME AND ESPECIALLY WHEN PARKED AT GATE .FIRST OFFICER NOTICED STRONGER SMELL AT GATE ALSO. MAINTENANCE HAS ISOLATED THE SOURCE OF THE ODOR TO THE APU. **SUPPLEMENTAL REPORT WILL BE SUBMITTED** (OPEN)