Narrative:

Took off out of lax, everything indicating normal. Very shortly after takeoff, passenger and flight attendants noticed 'fumes.' we could not identify source, elected to return to lax. Did not declare an emergency but received priority handling. Uneventful landing. Lax was not an alternate or destination on our dispatch. Received emergency vehicle escort to jetway. There was no smoke noticed. Callback conversation with reporter revealed the following information: the reporter stated the cause of the heavy fumes in unknown. The reporter said this is the first time any report of fumes or smoke in the cabin has gone unexplained. The reporter stated one fact was established with the cabin crew during this incident the aft lavatory smoke detector alarm sounded. The reporter stated both packs were operating with engine bleed air and the APU was shut down.

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Original NASA ASRS Text

Title: AN MD80 ON TKOF BTWN 500-9000 FT DIVERTED DUE TO PAX AND FLT ATTENDANTS RPTING HVY FUMES IN CABIN. CAUSE UNKNOWN.

Narrative: TOOK OFF OUT OF LAX, EVERYTHING INDICATING NORMAL. VERY SHORTLY AFTER TKOF, PAX AND FLT ATTENDANTS NOTICED 'FUMES.' WE COULD NOT IDENT SOURCE, ELECTED TO RETURN TO LAX. DID NOT DECLARE AN EMER BUT RECEIVED PRIORITY HANDLING. UNEVENTFUL LNDG. LAX WAS NOT AN ALTERNATE OR DEST ON OUR DISPATCH. RECEIVED EMER VEHICLE ESCORT TO JETWAY. THERE WAS NO SMOKE NOTICED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE CAUSE OF THE HVY FUMES IN UNKNOWN. THE RPTR SAID THIS IS THE FIRST TIME ANY RPT OF FUMES OR SMOKE IN THE CABIN HAS GONE UNEXPLAINED. THE RPTR STATED ONE FACT WAS ESTABLISHED WITH THE CABIN CREW DURING THIS INCIDENT THE AFT LAVATORY SMOKE DETECTOR ALARM SOUNDED. THE RPTR STATED BOTH PACKS WERE OPERATING WITH ENG BLEED AIR AND THE APU WAS SHUT DOWN.

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.