Narrative:

We departed with 1 pack inoperative. Climbing out I selected the cabin temperature to warmer and the temperature control valve was not responding in the automatic position. Since the previous flight complained that the cabin was cold; I wanted to try to keep the cabin comfortable on this leg. I selected manual to drive the temperature valve off of cold to start warming the cabin. I positioned the valve about the normal 10 O'clock position. I was then distraction by other duties and did not put the air conditioning control back to automatic. Captain noticed it was getting hot in the cockpit and we looked up to see what the problem was. We notice a high supply temperature and high rate of climb in the cabin. We also had a pressurization flow annunciator. The operating pack had shut down. I believe the cabin was only about 4000 ft at this time. We declared an emergency and descended to a lower altitude. During this time the pack came back on and flow returned to normal. I selected automatic and cooler on the temperature control and we observed the pressurization to be normal. We climbed back to FL230 and continued the rest of the flight. I believe this was a pilot induced problem resulting from using manual control instead of automatic. We both learned that in a 1 pack operation more attention must be devoted to the operating pack and automatic should only be used.

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Original NASA ASRS Text

Title: MD80 WAS DISPATCHED WITH ONE PACK INOP. REMAINING PACK SHUT DOWN; AND FLT CREW DECLARED EMER WHILE TROUBLESHOOTING ANOMALY.

Narrative: WE DEPARTED WITH 1 PACK INOP. CLBING OUT I SELECTED THE CABIN TEMP TO WARMER AND THE TEMP CTL VALVE WAS NOT RESPONDING IN THE AUTO POS. SINCE THE PREVIOUS FLT COMPLAINED THAT THE CABIN WAS COLD; I WANTED TO TRY TO KEEP THE CABIN COMFORTABLE ON THIS LEG. I SELECTED MANUAL TO DRIVE THE TEMP VALVE OFF OF COLD TO START WARMING THE CABIN. I POSITIONED THE VALVE ABOUT THE NORMAL 10 O'CLOCK POS. I WAS THEN DISTR BY OTHER DUTIES AND DID NOT PUT THE AIR CONDITIONING CTL BACK TO AUTO. CAPT NOTICED IT WAS GETTING HOT IN THE COCKPIT AND WE LOOKED UP TO SEE WHAT THE PROB WAS. WE NOTICE A HIGH SUPPLY TEMP AND HIGH RATE OF CLB IN THE CABIN. WE ALSO HAD A PRESSURIZATION FLOW ANNUNCIATOR. THE OPERATING PACK HAD SHUT DOWN. I BELIEVE THE CABIN WAS ONLY ABOUT 4000 FT AT THIS TIME. WE DECLARED AN EMER AND DSNDED TO A LOWER ALT. DURING THIS TIME THE PACK CAME BACK ON AND FLOW RETURNED TO NORMAL. I SELECTED AUTO AND COOLER ON THE TEMP CTL AND WE OBSERVED THE PRESSURIZATION TO BE NORMAL. WE CLBED BACK TO FL230 AND CONTINUED THE REST OF THE FLT. I BELIEVE THIS WAS A PLT INDUCED PROB RESULTING FROM USING MANUAL CTL INSTEAD OF AUTO. WE BOTH LEARNED THAT IN A 1 PACK OP MORE ATTN MUST BE DEVOTED TO THE OPERATING PACK AND AUTO SHOULD ONLY BE USED.

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.