As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 528 - SHORTLY AFTER TAKEOFF ORD COCKPIT RECEIVED INDICATION OF SMOKE IN AFT LEFT LAVATORY, FLIGHT ATTENDANTS GOT SAME ALERT ON FLIGHT ATTENDANT PANEL. NR 1 FLIGHT ATTENDANT OBSERVED HAZY SMOKE IN CABIN. RETURNED TO ORD AND LANDED WITHOUT INCIDENT. REPLACED NR 1&2 PACK RECIRCULATION COOLING FANS. INSPECTED PACK INLET AND EXHAUSTS. NO FOD NOTICED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)