As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD INFLIGHT, SMOKE AND FUMES REPORTED AFTER TAKEOFF. ENGINE ANTI ICE ON PACKS MEDIUM SETTING. SMOKE DISSIPATED WITH REDUCTION IN POWER AND TEMPERATURE CONTROLLERS SET TO FULL COLD. RETURNED TO ORD AND LANDED WITHOUT INCIDENT. REPLACED AUXILIARY POWER UNIT DUE TO OIL LEAK AT MATING SURFACE OF STARTER. PERFORMED PACK BURN. SYSTEM GROUND CHECKED NORMAL OPERATION.