Narrative:

Shortly after takeoff, one of my flight attendants reported that they and the passenger smelled a strong burnt smell in center of the main cabin. No smoke was visible, but a very strong smell of something burnt. My #1 flight attendant came into the cockpit and repeated the report and said that a non revenuing air carrier pilot also reported the same strong burnt smell. The odor/smell was not in the cockpit (based on the reports). I directed first officer, who was flying the aircraft, to return the aircraft to mia. The #1 flight attendant and I agreed to have the cabin prepared for landing. I initiated the air conditioning smoke abnormal. After turning off both recirculating fans and securing the right pack, I checked with the flight attendants and they said the smell had gone away, so I ended the procedure. First officer executed the ILS runway 9L at mia to a smooth, overweight (by 2700 pounds) landing. Callback conversation with reporter revealed the following information: the reporter stated the aircraft was a B737-800 and were climbing out of mia when the #1 flight attendant advised the cockpit of acrid fumes in the cabin. The reporter advised ATC the flight was returning but did not declare an emergency. The reporter said maintenance found the right pack air cycle machine failed and had allowed oil to enter the pack ducting.

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Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.