Narrative:

Flight attendant called and said extremely hot air exiting vents at foot level at location 2A & 2B. Crew selected cooler temperature of air conditioner. No change. Crew selected 'stby normal' on a/C panel. No change. Condition worsened. Crew selected trim air off. No change. Called maintenance; had nothing to add. Flight attendant said she and several passenger noticed horizontal red striations along first class panels on left side of airplane beneath windows. Relief pilot went back and also saw red coloration behind panels. Dispatch was also on the radio with captain. Declared emergency and took course directly back to ZZZ. Began dumping fuel. Dumped 10K pounds out of center tank. Turned packs off around 15K feet. Continued to descend. Unpressurized at 8 thousand feet. Requested runway X at ZZZ and emergency equipment standing by. Landed runway X with 340K pounds gross weight; flaps 25; 160 KTS. Flaps automatically retracted to 20 and 'trailing edge asymmetry' message displayed on EICAS. Touched down first 500 ft. Of runway. Landing uneventful. Stopped on runway. Shut down engines. Received 'all clear' from ground fire department. Restarted engines and APU. Ran packs off of APU. No problems as we taxied to the gate.callback conversation with reporter revealed the following information: when the packs were turned off at 15000 ft the hot air flow ceased and the cabin altitude did not exceed 10000 ft during the descent. After landing and all clear from crash fire rescue equipment; the engines were restarted and the packs were run off the APU with no problems. Maintenance believed that the anomaly was caused by a stuck trim air valve.

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Original NASA ASRS Text

Title: B767 FLT CREW CLIMBING THROUGH FL180 RPTS UNCONTROLLABLE HOT AIR FROM FLOOR LEVEL AIR VENTS AT SEATS 2A AND B. AN EMERGENCY IS DECLARED WITH RETURN TO DEP ARPT.

Narrative: FLT ATTENDANT CALLED AND SAID EXTREMELY HOT AIR EXITING VENTS AT FOOT LEVEL AT LOCATION 2A & 2B. CREW SELECTED COOLER TEMP OF AIR CONDITIONER. NO CHANGE. CREW SELECTED 'STBY NORMAL' ON A/C PANEL. NO CHANGE. CONDITION WORSENED. CREW SELECTED TRIM AIR OFF. NO CHANGE. CALLED MAINT; HAD NOTHING TO ADD. FLT ATTENDANT SAID SHE AND SEVERAL PAX NOTICED HORIZONTAL RED STRIATIONS ALONG FIRST CLASS PANELS ON L SIDE OF AIRPLANE BENEATH WINDOWS. RELIEF PILOT WENT BACK AND ALSO SAW RED COLORATION BEHIND PANELS. DISPATCH WAS ALSO ON THE RADIO WITH CAPT. DECLARED EMER AND TOOK COURSE DIRECTLY BACK TO ZZZ. BEGAN DUMPING FUEL. DUMPED 10K LBS OUT OF CENTER TANK. TURNED PACKS OFF AROUND 15K FEET. CONTINUED TO DSND. UNPRESSURIZED AT 8 THOUSAND FEET. REQUESTED RWY X AT ZZZ AND EMER EQUIPMENT STANDING BY. LANDED RWY X WITH 340K LBS GROSS WEIGHT; FLAPS 25; 160 KTS. FLAPS AUTOMATICALLY RETRACTED TO 20 AND 'TRAILING EDGE ASYMMETRY' MESSAGE DISPLAYED ON EICAS. TOUCHED DOWN FIRST 500 FT. OF RWY. LNDG UNEVENTFUL. STOPPED ON RWY. SHUT DOWN ENGINES. RECEIVED 'ALL CLEAR' FROM GND FIRE DEPT. RESTARTED ENGINES AND APU. RAN PACKS OFF OF APU. NO PROBLEMS AS WE TAXIED TO THE GATE.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: WHEN THE PACKS WERE TURNED OFF AT 15000 FT THE HOT AIR FLOW CEASED AND THE CABIN ALT DID NOT EXCEED 10000 FT DURING THE DSCNT. AFTER LNDG AND ALL CLR FROM CFR; THE ENGINES WERE RESTARTED AND THE PACKS WERE RUN OFF THE APU WITH NO PROBLEMS. MAINT BELIEVED THAT THE ANOMALY WAS CAUSED BY A STUCK TRIM AIR VALVE.

Data retrieved from NASA's ASRS site as of January 2009 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.