As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PIT - FLT 44 - PILOT NOTED BURNED OIL SMELL FROM AIR CONDITIONING SYSTEM. MAINTENANCE RAN AND ISOLATED BOTH PACKS. A SLIGHT ODOR WAS NOTED. PACKS WERE RUN AT FULL HOT AND THE ODOR DISSIPATED. ON A FOLLOWING FLIGHT, THE ODOR RETURNED. MAINTENANCE REPLACED THE APU. (M)