As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 1229 - AFTER TAKEOFF ORD, FLIGHT ATTENDANTS REPORTED SMOKE IN THE CABIN. RETURNED TO ORD AND LANDED OVERWEIGHT WITHOUT INCIDENT. FOUND APU LEAKING OIL FROM THE MASTER CHIP DETECTOR REPLACED APU ASSEMBLY AND LEAKED CHECKED GOOD. ACCOMPLISHED PACK BURN, NO SMELL NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)