A B737-800 ON CLB AT 12000 FT DIVERTED DUE TO FUMES IN THE CABIN CAUSED BY A FAILED R PACK AIR CYCLE MACHINE.

Narrative

SHORTLY AFTER TKOF; ONE OF MY FLT ATTENDANTS RPTED THAT THEY AND THE PAX SMELLED A STRONG BURNT SMELL IN CTR OF THE MAIN CABIN. NO SMOKE WAS VISIBLE; BUT A VERY STRONG SMELL OF SOMETHING BURNT. MY #1 FLT ATTENDANT CAME INTO THE COCKPIT AND REPEATED THE RPT AND SAID THAT A NON REVENUING ACR PLT ALSO RPTED THE SAME STRONG BURNT SMELL. THE ODOR/SMELL WAS NOT IN THE COCKPIT (BASED ON THE RPTS). I DIRECTED FO; WHO WAS FLYING THE ACFT; TO RETURN THE ACFT TO MIA. THE #1 FLT ATTENDANT AND I AGREED TO HAVE THE CABIN PREPARED FOR LNDG. I INITIATED THE AIR CONDITIONING SMOKE ABNORMAL. AFTER TURNING OFF BOTH RECIRCULATING FANS AND SECURING THE R PACK; I CHKED WITH THE FLT ATTENDANTS AND THEY SAID THE SMELL HAD GONE AWAY; SO I ENDED THE PROC. FO EXECUTED THE ILS RWY 9L AT MIA TO A SMOOTH; OVERWT (BY 2700 LBS) LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A B737-800 AND WERE CLBING OUT OF MIA WHEN THE #1 FLT ATTENDANT ADVISED THE COCKPIT OF ACRID FUMES IN THE CABIN. THE RPTR ADVISED ATC THE FLT WAS RETURNING BUT DID NOT DECLARE AN EMER. THE RPTR SAID MAINT FOUND THE R PACK AIR CYCLE MACHINE FAILED AND HAD ALLOWED OIL TO ENTER THE PACK DUCTING.