Narrative:

Level at 16;000 ft we received a master warning 'cabin press' light. I noted that the cabin pressure was at 10;000 ft and increasing slowly. I recognized that this was not a rapid decompression and did not require an emergency descent. I notified ATC that we had pressurization problem and needed to descend to 10;000 ft. We were immediately cleared to descend. We did the QRH for 'cabin press'; which resolved the situation; and continued to destination without further incident. This event occurred because during 'before takeoff checklist' and also the 'climb checklist' we both mistakenly verified the bleed flow position; but not the switch position. During both checklists the packs were set correctly; min for takeoff and norm for climb; but the bleeds were left in the off position. I feel that fatigue played a role in this incident as well as the dark conditions in the cockpit. This was our fourth night of cdo (continuous duty overnight); and while I did sleep during the previous day and during the hotel stay I think that; after four days of a choppy/disruptive sleep pattern; fatigue is inevitable. Prior to the flight I felt ok; certainly not what I would consider fatigued. When we got off the plane in ZZZ though I did feel tired. Perhaps having to cope with the abnormal situation added to the feeling of fatigue. The dark conditions in the cockpit also contributed because of the difficulty in verifying the bleed switch position visually in the dark cockpit. I will certainly be more vigilant in the future regarding my observations during the before takeoff checklist; although this checklist is sometimes run during taxi; and during the climb checklist. I will also physically touch the bleed switches during my climb flow and make sure to visually verify the switch position and again when reading the checklist. These are both things that I normally do; this is part of the reason I think fatigue played a role in this event; I deviated from my normal way of doing things without even realizing it. I think that 4 cdos in a row is too many. I feel that 2 is acceptable and 3 should be the max.

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Original NASA ASRS Text

Title: Q400 flight crew experienced a cabin altitude warning light while in cruise at 16;000 FT. A descent is initiated and the QRH consulted; it is discovered that the bleeds were never turned on after engine start. Flight continues to destination.

Narrative: Level at 16;000 FT we received a master warning 'CABIN PRESS' light. I noted that the cabin pressure was at 10;000 FT and increasing slowly. I recognized that this was not a rapid decompression and did not require an emergency descent. I notified ATC that we had pressurization problem and needed to descend to 10;000 FT. We were immediately cleared to descend. We did the QRH for 'CABIN PRESS'; which resolved the situation; and continued to destination without further incident. This event occurred because during 'Before Takeoff Checklist' and also the 'Climb Checklist' we both mistakenly verified the bleed flow position; but not the switch position. During both checklists the packs were set correctly; MIN for takeoff and NORM for climb; but the bleeds were left in the off position. I feel that fatigue played a role in this incident as well as the dark conditions in the cockpit. This was our fourth night of CDO (Continuous Duty Overnight); and while I did sleep during the previous day and during the hotel stay I think that; after four days of a choppy/disruptive sleep pattern; fatigue is inevitable. Prior to the flight I felt OK; certainly not what I would consider fatigued. When we got off the plane in ZZZ though I did feel tired. Perhaps having to cope with the abnormal situation added to the feeling of fatigue. The dark conditions in the cockpit also contributed because of the difficulty in verifying the bleed switch position visually in the dark cockpit. I will certainly be more vigilant in the future regarding my observations during the before takeoff checklist; although this checklist is sometimes run during taxi; and during the climb checklist. I will also physically touch the bleed switches during my climb flow and make sure to visually verify the switch position and again when reading the checklist. These are both things that I normally do; this is part of the reason I think fatigue played a role in this event; I deviated from my normal way of doing things without even realizing it. I think that 4 CDOs in a row is too many. I feel that 2 is acceptable and 3 should be the max.

Data retrieved from NASA's ASRS site as of April 2012 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.