What was found
(CAN) PRIOR TO DECENT A STRONG ODOR WAS EMITTED FROM THE AIR-CONDITIONING SYSTEM. SHORTLY AFTERWARDS ONE OF THE FLIGHT ATTENDANTS ADVISED THE FLIGHT CREW THAT SMOKE WAS FILLING THE REAR CABIN AREA. THE AIRCRAFT WAS DIVERTED AND LANDED WITHOUT FURTHER INCIDENT. ENGINEERING INVESTIGATION REVEALED THAT THE NR 1 AIR-CONDITIONING PACK ACM HAD FAILED WITH THE ACM TURBINE SEIZED. THE ODOR AND SMOKE IN THE CABIN WERE DUE TO LEAKAGE AND HEATING OF THE ACM LUBRICATING OIL DURING THE ACM FAILING AND PRIOR TO AIR-CONDITIONING PACK SHUTDOWN. THE ACM WAS CHANGED AND THE AIRCRAFT WAS RETURNED TO SERVICE WITHOUT FURTHER INCIDENT.