As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SFO - FLT 1992 - DURING FLIGHT, THE FLIGHT ATTENDANT REPORTED SMOKE VISIBLE FROM AIR CONDITIONER VENTS. RETURNED AND LANDED SFO WITHOUT INCIDENT. REPLACED COALESCER BAGS AND ACCOMPLISHED PACK BURN-OUT. UNABLE TO DUPLICATE SMOKE. SYSTEM GROUND CHECKED, NORMAL OPERATION. (X)