AN A320 CREW EXPERIENCED CABIN SMOKE OF UNKNOWN ORIGIN; DECLARED AN EMER AND LANDED AT THEIR DEST. QRH CHKLIST CLRED SMOKE.

Narrative

DEPARTED ZZZ1 TO ZZZ WITH 154 PAX; 5 CREW; 2 JUMPSEATERS; WITH A NORMAL START; TAXI; TKOF; AND CLB WITH THE FO FLYING. AT APPROX 150 NM SSE OF ZZZ1 AT AN ALT OF FL280; AN ACRID SMOKE SMELL APPEARED. JUST AS FLT DECK CREW NOTICED THE SMELL; THE FIRST FLT ATTENDANT CALLED TO INFORM US THAT SMOKE HAD APPEARED IN THE MAIN CABIN. THE FO AND I DONNED OUR OXYGEN MASKS AND DECLARED AN EMER AND REQUESTED A DSCNT AND DIRECT ROUTING TO ZZZ. AS WE DSNDED; I HAD THE FO CONTINUE TO FLY AS I RAN AND COMPLETED THE SMOKE REMOVAL CHKLIST FROM THE QRH. THE SMOKE AND SMELL BEGAN TO DISSIPATE AND THE CABIN CREW RPTED THAT SMOKE HAD CLRED. I ADVISED THE FIRST FLT ATTENDANT TO PREPARE CABIN FOR PRECAUTIONARY LNDG IN ZZZ AND TIME REMAINING. WITH THE PAX ADVISED OF THE SITUATION AND ZZZ OPS NOTIFIED; WE CONTINUED TO ZZZ FOR A NORMAL LNDG ON RWY 25R AND TAXIED TO GATE WITHOUT INCIDENT. THE END RESULT OF THIS EVENT WAS IN LARGE PART DUE TO THE EXEMPLARY FLYING SKILLS OF MY FO AND EXTREME PROFESSIONALISM AND CRM OF MY CABIN CREW. SUPPLEMENTAL INFO FROM ACN 654319: THE CAPT WAS QUICK TO PROPERLY EVALUATE THE SITUATION AND LED HIS CREW WITH CONSUMMATE CRM SKILLS. COM WAS THE KEY. IN ADDITION TO THE CAPT; THE CABIN CREW DID EXTREMELY WELL CONSIDERING THE CIRCUMSTANCES -- SMOKE IN THE CABIN WITH UNKNOWN ORIGIN. THEIR COOL HEADS PREVAILED AND THE NECESSARY TASKS WERE ACCOMPLISHED; RESULTING IN A SAFE LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: FO STATED THAT THE AIR CYCLE MACHINE OVERHEATED AND SEIZED; CAUSING SMOKE IN THE AIR CONDITIONING DUCT. HE STATED THEY HAD NO ECAM MESSAGE UNTIL AFTER PARKING AND SHUTTING DOWN AT THE GATE. HE ALSO FELT THE QRH PROC COVERED THE SITUATION WELL AND CLRED THE CABIN OF SMOKE.