Narrative:

During climb out from dfw at approximately FL210, received warning horn indicating cabin pressure loss. So noticed cabin pressure rising through 11000 ft and attempted to arrest it. I immediately declared an emergency and started a descent to 10000 ft. The cabin pressure loss was stopped at approximately 11500 ft with the aircraft in a descent. At 10000 ft, the cabin altitude had been reduced to 8500 ft but no lower. Passenger oxygen masks were not deployed and we returned to dfw, dumping approximately 12000 pounds fuel en route to avoid overweight landing with possible structural damage. Uneventful landing at dfw.

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Original NASA ASRS Text

Title: AN ACR B727 FLC LOSES PRESSURIZATION AT FL210 DECLARES AN EMER AND RETURNS TO DFW.

Narrative: DURING CLBOUT FROM DFW AT APPROX FL210, RECEIVED WARNING HORN INDICATING CABIN PRESSURE LOSS. SO NOTICED CABIN PRESSURE RISING THROUGH 11000 FT AND ATTEMPTED TO ARREST IT. I IMMEDIATELY DECLARED AN EMER AND STARTED A DSCNT TO 10000 FT. THE CABIN PRESSURE LOSS WAS STOPPED AT APPROX 11500 FT WITH THE ACFT IN A DSCNT. AT 10000 FT, THE CABIN ALT HAD BEEN REDUCED TO 8500 FT BUT NO LOWER. PAX OXYGEN MASKS WERE NOT DEPLOYED AND WE RETURNED TO DFW, DUMPING APPROX 12000 LBS FUEL ENRTE TO AVOID OVERWT LNDG WITH POSSIBLE STRUCTURAL DAMAGE. UNEVENTFUL LNDG AT DFW.

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.