Narrative:

FL350, engine and wing anti-ice on, airborne about 2 hours, flow light came on. Right pack flow indication 7 O'clock position, left pack 9:30 O'clock. Cabin about 8800 ft climbing about 300 FPM. Followed quick reference handbook for pack no flow indicated made it worse. Cabin climbing at 550 FPM and left pack reads about 8 O'clock position cabin at about 9000 ft. Told first officer to declare an emergency and get lower altitude. Center gave us FL290. I began emergency descent with cabin at 9300 ft and climbing. Told first officer to declare an emergency and get lower. Center gave us FL180 with a turn off course. TA on TCASII as we break out IMC. Other aircraft in sight about 5-6 mi at 2 O'clock. Cabin peaks at about 10500 ft with master warning and cabin altitude alert. Tell first officer we are going to 10000 ft and get clearance. Center issues clearance to 10000 ft before we ask for it. At 10000 ft both packs come back on-line on their own. Bna is 30 mi away but closed to WX. I elect to go to mem. Packs operated ok so we stair-step at 2000 ft intervals to FL200. Cabin pressure normal. We elect to continue to dfw after conference with dispatch. I check with first officer after everything settled and ask if he ever declared an emergency, he said no I forgot. I called center and made sure they knew we had declared an emergency (ZME). Center folks did a great job. Passenger masks did not drop, advised a flight attendant of the problem. Uneventful flight and landing.

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Original NASA ASRS Text

Title: FLC UNABLE TO MAINTAIN PRESSURIZATION AND COMMENCES EMER DSCNT.

Narrative: FL350, ENG AND WING ANTI-ICE ON, AIRBORNE ABOUT 2 HRS, FLOW LIGHT CAME ON. R PACK FLOW INDICATION 7 O'CLOCK POS, L PACK 9:30 O'CLOCK. CABIN ABOUT 8800 FT CLBING ABOUT 300 FPM. FOLLOWED QUICK REF HANDBOOK FOR PACK NO FLOW INDICATED MADE IT WORSE. CABIN CLBING AT 550 FPM AND L PACK READS ABOUT 8 O'CLOCK POS CABIN AT ABOUT 9000 FT. TOLD FO TO DECLARE AN EMER AND GET LOWER ALT. CTR GAVE US FL290. I BEGAN EMER DSCNT WITH CABIN AT 9300 FT AND CLBING. TOLD FO TO DECLARE AN EMER AND GET LOWER. CTR GAVE US FL180 WITH A TURN OFF COURSE. TA ON TCASII AS WE BREAK OUT IMC. OTHER ACFT IN SIGHT ABOUT 5-6 MI AT 2 O'CLOCK. CABIN PEAKS AT ABOUT 10500 FT WITH MASTER WARNING AND CABIN ALT ALERT. TELL FO WE ARE GOING TO 10000 FT AND GET CLRNC. CTR ISSUES CLRNC TO 10000 FT BEFORE WE ASK FOR IT. AT 10000 FT BOTH PACKS COME BACK ON-LINE ON THEIR OWN. BNA IS 30 MI AWAY BUT CLOSED TO WX. I ELECT TO GO TO MEM. PACKS OPERATED OK SO WE STAIR-STEP AT 2000 FT INTERVALS TO FL200. CABIN PRESSURE NORMAL. WE ELECT TO CONTINUE TO DFW AFTER CONFERENCE WITH DISPATCH. I CHK WITH FO AFTER EVERYTHING SETTLED AND ASK IF HE EVER DECLARED AN EMER, HE SAID NO I FORGOT. I CALLED CTR AND MADE SURE THEY KNEW WE HAD DECLARED AN EMER (ZME). CTR FOLKS DID A GREAT JOB. PAX MASKS DID NOT DROP, ADVISED A FLT ATTENDANT OF THE PROB. UNEVENTFUL FLT AND LNDG.

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.