As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - FLT 1639 - ON TAKEOFF SMOKE NOTICED IN CABIN THEN QUICKLY DISSIPATED. REAPPEARED DURING DESCENT TO DFW. LANDED DFW WITHOUT INCIDENT. REPLACED AUXILIARY POWER UNIT, ACCOMPLISHED PACK BURNOUT. SYSTEM GROUND CHECK NORMAL OPERATION. (M)