Narrative:

During ground operations; packs were cycled off to attempt to work the heating-air conditioning system. They were never discovered as off prior to flight. There is not procedures for verifying this; nor is it a checklist item at any time. Flight departed and executed turn for departure. Cleared direct through about 8500 ft; and proceeded on course. Because of quick climb; and high departure altitude; the 'after takeoff checklist' was completed as we passed through 10000 ft. Just after; the cabin pressure warning illuminated; and we immediately leveled off; and followed the emergency items checklist. We notified ATC and were immediately given descent; and turn toward ZZZ. Captain quickly informed the flight attendants that it would be a return to field; normal landing; 5 mins. Reaching about 18 DME we were cleared visual approach. During this time; I flew the plane; as captain finished the checklist; and recalculated for overweight landing. It was at this time (after already on downwind) that he reached the item regarding packs. I believe he cycled them on at that point; and shortly after the aircraft began to pressurize. Completing the normal descent and landing checklists; we landed without incident; at less than 200 FPM descent; and taxied to the gate. I contacted dispatch to answer their questions; and captain contacted maintenance. It was determined that the aircraft was safe; and we then continued on. 1 passenger reported feeling a little nauseous; but not sure that it was related. I believe she was the one who departed the plane; for fear she would not be able to make her connection and not because of illness. No other passenger reported any problems; medical or otherwise; and seemed really only concerned with the delay to catch a connection. Flight departed without further incident. Packs selected 'automatic/man' is not listed on any procedure or checklist to rechk prior to takeoff. The only time it is discussed is in the captain's originating checklist; and this was our second leg with that aircraft that day; so this check was not accomplished. During my short time here; I have had more than 10 different explanations as to the workings of the air conditioning system from different check airmen; capts; and first officer's. There is no clear guidance as the operation of this system from the company; we just have to figure it out. Further; I suggest a line be added to the 'taxi checklist' right before 'bleeds on': 'pack -- automatic/man' to allow successful operation of the air conditioning; as well as pressurization of the aircraft. I believe this would have prevented this return to field; and the further delays -- disruptions to passenger; aircraft; and crews.

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Original NASA ASRS Text

Title: DASH 8 FO REPORTS CABIN ALTITUDE WARNING AT 10000 FEET ON CLIMB OUT. PACKS ARE DISCOVERED OFF DURING THE RETURN TO LAND.

Narrative: DURING GND OPS; PACKS WERE CYCLED OFF TO ATTEMPT TO WORK THE HEATING-AIR CONDITIONING SYS. THEY WERE NEVER DISCOVERED AS OFF PRIOR TO FLT. THERE IS NOT PROCS FOR VERIFYING THIS; NOR IS IT A CHKLIST ITEM AT ANY TIME. FLT DEPARTED AND EXECUTED TURN FOR DEP. CLRED DIRECT THROUGH ABOUT 8500 FT; AND PROCEEDED ON COURSE. BECAUSE OF QUICK CLB; AND HIGH DEP ALT; THE 'AFTER TKOF CHKLIST' WAS COMPLETED AS WE PASSED THROUGH 10000 FT. JUST AFTER; THE CABIN PRESSURE WARNING ILLUMINATED; AND WE IMMEDIATELY LEVELED OFF; AND FOLLOWED THE EMER ITEMS CHKLIST. WE NOTIFIED ATC AND WERE IMMEDIATELY GIVEN DSCNT; AND TURN TOWARD ZZZ. CAPT QUICKLY INFORMED THE FLT ATTENDANTS THAT IT WOULD BE A RETURN TO FIELD; NORMAL LNDG; 5 MINS. REACHING ABOUT 18 DME WE WERE CLRED VISUAL APCH. DURING THIS TIME; I FLEW THE PLANE; AS CAPT FINISHED THE CHKLIST; AND RECALCULATED FOR OVERWT LNDG. IT WAS AT THIS TIME (AFTER ALREADY ON DOWNWIND) THAT HE REACHED THE ITEM REGARDING PACKS. I BELIEVE HE CYCLED THEM ON AT THAT POINT; AND SHORTLY AFTER THE ACFT BEGAN TO PRESSURIZE. COMPLETING THE NORMAL DSCNT AND LNDG CHKLISTS; WE LANDED WITHOUT INCIDENT; AT LESS THAN 200 FPM DSCNT; AND TAXIED TO THE GATE. I CONTACTED DISPATCH TO ANSWER THEIR QUESTIONS; AND CAPT CONTACTED MAINT. IT WAS DETERMINED THAT THE ACFT WAS SAFE; AND WE THEN CONTINUED ON. 1 PAX RPTED FEELING A LITTLE NAUSEOUS; BUT NOT SURE THAT IT WAS RELATED. I BELIEVE SHE WAS THE ONE WHO DEPARTED THE PLANE; FOR FEAR SHE WOULD NOT BE ABLE TO MAKE HER CONNECTION AND NOT BECAUSE OF ILLNESS. NO OTHER PAX RPTED ANY PROBS; MEDICAL OR OTHERWISE; AND SEEMED REALLY ONLY CONCERNED WITH THE DELAY TO CATCH A CONNECTION. FLT DEPARTED WITHOUT FURTHER INCIDENT. PACKS SELECTED 'AUTO/MAN' IS NOT LISTED ON ANY PROC OR CHKLIST TO RECHK PRIOR TO TKOF. THE ONLY TIME IT IS DISCUSSED IS IN THE CAPT'S ORIGINATING CHKLIST; AND THIS WAS OUR SECOND LEG WITH THAT ACFT THAT DAY; SO THIS CHK WAS NOT ACCOMPLISHED. DURING MY SHORT TIME HERE; I HAVE HAD MORE THAN 10 DIFFERENT EXPLANATIONS AS TO THE WORKINGS OF THE AIR CONDITIONING SYS FROM DIFFERENT CHK AIRMEN; CAPTS; AND FO'S. THERE IS NO CLR GUIDANCE AS THE OP OF THIS SYS FROM THE COMPANY; WE JUST HAVE TO FIGURE IT OUT. FURTHER; I SUGGEST A LINE BE ADDED TO THE 'TAXI CHKLIST' RIGHT BEFORE 'BLEEDS ON': 'PACK -- AUTO/MAN' TO ALLOW SUCCESSFUL OP OF THE AIR CONDITIONING; AS WELL AS PRESSURIZATION OF THE ACFT. I BELIEVE THIS WOULD HAVE PREVENTED THIS RETURN TO FIELD; AND THE FURTHER DELAYS -- DISRUPTIONS TO PAX; ACFT; AND CREWS.

Data retrieved from NASA's ASRS site as of May 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.