As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF CABIN AND COCKPIT FILLED WITH FUMES, SMELLED LIKE SOMETHING OVERHEATING, OCCURED WHEN SWITCHING FROM APU TO ENGINE BLEED AIR. AIRCRAFT RETURNED TO DEN AND LANDED OVERWEIGHT. COMPLETED PACK BURNOUT PROCEDURE PER MM ON BOTH ENG AND APU BLEED AIR, NO DISCREPANCIES NOTED. COMPLIED WITH OVERWEIGHT LANDING INSPECTION. (M)