What was found
CREW REPORTED SMOKE, ODOR IN AFT CABIN ON DESCENT WITH AFT RIGHT LAVATORY SMOKE DETECTOR ALERTING MOMENTARILY. MAINTENANCE BOROSCOPED BOTH ENGINES LOOKING FOR SIGNS OF OIL RESIDUE, NONE FOUND. REQUEST MAINTENANCE REPLACED THE RECIRCULATION FAN AND FILTER. EVIDENCE OF OIL WAS FOUND IN BOTH PACK DUCTS, SO BOTH PACKS WERE PUT ON MEL. SHIP WAS FERRIED AND MAINTENANCE COMPLIED WITH ALL MCC REQUESTED TASKS ON N/R CARDS 1-15. RAN ENGINES AT TAKEOFF POWER WITH PACKS SET TO HOT AND ACFT PRESSURIZED. NO SMOKE OR ODOR PRESENT.