Narrative:

All procedures were normal until approaching runway 35L in dfw. The temperature in the cockpit was rising (approximately 90 degrees) and we had tried to adjust it by lowering the temperature controller and then by going to manual. The temperature in the cockpit continued to rise and the flight deck temperature advisory message illuminated on the EICAS. The pom procedure was accomplished with neg results. The decision was made to not takeoff and to return to the gate which took approximately 20 mins due to the number of aircraft waiting to takeoff. Maintenance verified that the left pack was inoperative and placarded the left pack inoperative. At that point, the aircraft restrictions manual was consulted which limited our altitude to 35000'. Because of a lower cruising and the WX in atl, a request was made to operations to increase the fuel load to 29000 pounds. The third flight release had a block fuel of 29000 pounds with a cruising altitude of 33000'. All checklists were reaccomplished prior to leaving the gate. On departure at approximately 4000', the left engine bleed light illuminated on the EICAS. After passing 10000', the pom was consulted and the appropriate action was taken. It was also noted at this time that if aircraft anti-icing was required the isolation valve had to be opened. On descent at approximately 27000', the aircraft anti-icing was activated due to the WX in the area. At approximately 25000' the cabin altitude warning activated. Both crew members noted the cabin altitude was approximately 10000'. As per the departure briefing by the captain, the captain continued to fly the aircraft while the first officer evaluated the problem. At this time the responsibilities were split between the crew members and each were accomplishing different tasks. The captain called ATC and requested clearance to 10000' due to a cabin pressurization problem. ATC responded for us to standby. The captain then notified ATC that we could not standby and that we were departing 24700' for 10000'. ATC then gave us clearance to 10000'. An emergency descent was accomplished. During this time the first officer noted the cabin altitude was approximately 10000', rate of climb was between 100 and 200 FPM, outflow value was about 3/4 open, and there were no other indications which would normally be associated with a pressurization problem. Additionally it was noted that cabin had not exceeded 14000' and the passenger oxygen was not required. The pressurization controller was placed to automatic 2 with no results. At this point, a crew decision was made to done the oxy masks and the first officer put his mask on. The captain then temporarily xferred control of aircraft to first officer while he put his mask on. The captain then requested the first officer to notify the faic as to the cabin pressurization problem. The faic informed him that no problems existed in the cabin. The emergency descent and loss of pressurization checklists were accomplished. After leveling off, a PA was accomplished to inform the passengers that company agents would meet the aircraft at the gate in case anyone had experienced a problem during the descent. The remainder of the flight preceeded uneventfully. To our knowledge none of the passengers asked for or required medical attention upon deplaning. I believe the use of anti-ice, which caused bleed air to be used was part of problem. The one pack could no longer maintain cabin pressure.

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Original NASA ASRS Text

Title: FLC MISMANAGEMENT OF ONE PACK INOP PRESSURIZATION SYSTEM LEADS TO EMERGENCY DESCENT.

Narrative: ALL PROCS WERE NORMAL UNTIL APCHING RWY 35L IN DFW. THE TEMP IN THE COCKPIT WAS RISING (APPROX 90 DEGS) AND WE HAD TRIED TO ADJUST IT BY LOWERING THE TEMP CTLR AND THEN BY GOING TO MANUAL. THE TEMP IN THE COCKPIT CONTINUED TO RISE AND THE FLT DECK TEMP ADVISORY MESSAGE ILLUMINATED ON THE EICAS. THE POM PROC WAS ACCOMPLISHED WITH NEG RESULTS. THE DECISION WAS MADE TO NOT TKOF AND TO RETURN TO THE GATE WHICH TOOK APPROX 20 MINS DUE TO THE NUMBER OF ACFT WAITING TO TKOF. MAINT VERIFIED THAT THE L PACK WAS INOPERATIVE AND PLACARDED THE L PACK INOP. AT THAT POINT, THE ACFT RESTRICTIONS MANUAL WAS CONSULTED WHICH LIMITED OUR ALT TO 35000'. BECAUSE OF A LOWER CRUISING AND THE WX IN ATL, A REQUEST WAS MADE TO OPS TO INCREASE THE FUEL LOAD TO 29000 LBS. THE THIRD FLT RELEASE HAD A BLOCK FUEL OF 29000 LBS WITH A CRUISING ALT OF 33000'. ALL CHKLISTS WERE REACCOMPLISHED PRIOR TO LEAVING THE GATE. ON DEP AT APPROX 4000', THE L ENG BLEED LIGHT ILLUMINATED ON THE EICAS. AFTER PASSING 10000', THE POM WAS CONSULTED AND THE APPROPRIATE ACTION WAS TAKEN. IT WAS ALSO NOTED AT THIS TIME THAT IF ACFT ANTI-ICING WAS REQUIRED THE ISOLATION VALVE HAD TO BE OPENED. ON DSNT AT APPROX 27000', THE ACFT ANTI-ICING WAS ACTIVATED DUE TO THE WX IN THE AREA. AT APPROX 25000' THE CABIN ALT WARNING ACTIVATED. BOTH CREW MEMBERS NOTED THE CABIN ALT WAS APPROX 10000'. AS PER THE DEP BRIEFING BY THE CAPT, THE CAPT CONTINUED TO FLY THE ACFT WHILE THE F/O EVALUATED THE PROB. AT THIS TIME THE RESPONSIBILITIES WERE SPLIT BTWN THE CREW MEMBERS AND EACH WERE ACCOMPLISHING DIFFERENT TASKS. THE CAPT CALLED ATC AND REQUESTED CLRNC TO 10000' DUE TO A CABIN PRESSURIZATION PROB. ATC RESPONDED FOR US TO STANDBY. THE CAPT THEN NOTIFIED ATC THAT WE COULD NOT STANDBY AND THAT WE WERE DEPARTING 24700' FOR 10000'. ATC THEN GAVE US CLRNC TO 10000'. AN EMER DSNT WAS ACCOMPLISHED. DURING THIS TIME THE F/O NOTED THE CABIN ALT WAS APPROX 10000', RATE OF CLB WAS BTWN 100 AND 200 FPM, OUTFLOW VALUE WAS ABOUT 3/4 OPEN, AND THERE WERE NO OTHER INDICATIONS WHICH WOULD NORMALLY BE ASSOCIATED WITH A PRESSURIZATION PROB. ADDITIONALLY IT WAS NOTED THAT CABIN HAD NOT EXCEEDED 14000' AND THE PAX OXYGEN WAS NOT REQUIRED. THE PRESSURIZATION CTLR WAS PLACED TO AUTO 2 WITH NO RESULTS. AT THIS POINT, A CREW DECISION WAS MADE TO DONE THE OXY MASKS AND THE F/O PUT HIS MASK ON. THE CAPT THEN TEMPORARILY XFERRED CTL OF ACFT TO F/O WHILE HE PUT HIS MASK ON. THE CAPT THEN REQUESTED THE F/O TO NOTIFY THE FAIC AS TO THE CABIN PRESSURIZATION PROB. THE FAIC INFORMED HIM THAT NO PROBS EXISTED IN THE CABIN. THE EMER DSNT AND LOSS OF PRESSURIZATION CHKLISTS WERE ACCOMPLISHED. AFTER LEVELING OFF, A PA WAS ACCOMPLISHED TO INFORM THE PAXS THAT COMPANY AGENTS WOULD MEET THE ACFT AT THE GATE IN CASE ANYONE HAD EXPERIENCED A PROB DURING THE DSNT. THE REMAINDER OF THE FLT PRECEEDED UNEVENTFULLY. TO OUR KNOWLEDGE NONE OF THE PAXS ASKED FOR OR REQUIRED MEDICAL ATTN UPON DEPLANING. I BELIEVE THE USE OF ANTI-ICE, WHICH CAUSED BLEED AIR TO BE USED WAS PART OF PROB. THE ONE PACK COULD NO LONGER MAINTAIN CABIN PRESSURE.

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.