What was found
(CAN) SMOKE DETECTED IN CABIN, EMERGENCY DECLARED, AIR PACK REGULATOR FAULT ON UPPER ECAM. ON ARRIVAL WHITE SMOKE NOTED ON OPENING PACK DOOR. MAINTENANCE ACTION INVOLVED CHANGING #2 BYPASS VALVE. ACM FOUND SEIZED AND TURBINE THREW BLADE. FURTHER INVESTIGATION REVEALED BLADE BROKE FROM FAN AND NOT TURBINE. AFTER ACM AND TURBINE BYPASS VALVE REPLACED, ENGINES RAN AND PACKS OPERATED CHECKS SERVICEABLE.