Narrative:

While departing on climb out we missed turning on the bleed air system. The weather was low overcast and the visibility was 1 mile. Our initial indication was a call from the flight attendant letting us know that the oxygen masks had deployed. This occurred climbing through 12;500 ft. Upon receiving this information we immediately turned on the bleed air system and checked that the aircraft was pressurizing properly. Our final cruise altitude was 13;000 ft. We continued the flight to our filed destination normally. Contributing factors that lead to our missing the bleed air system were: task saturation due to high elevation airport; weather; and air traffic control frequency changes while on the IFR departure procedure; and the master warning flasher to indicate a pressurization problem climbing through 10;000 ft not working properly. My captain normally reaches to turn on the bleed air on his after takeoff flow. However; he needed to make sure that the de ice boots were on as we were climbing into icing conditions on this particular flight; thus interrupting his flow. At acceleration altitude we also changed from tower to center. I was flying the IFR departure procedure and my captain was backing me up; as he should. Only having 3;000 ft to climb; he had not gotten to the climb check reaching 10;000 ft; which would have been another way to have caught that the cabin was not pressurizing before the oxygen masks dropped. We did not get a master warning flasher indicating a pressurization issue. After the masks dropped; we discovered that some of the masks did not drop properly. Upon termination of the flight; the oxygen masks; the oxygen masks that did not work properly; and the master warning flasher were properly written up. A future event might be prevented if the after takeoff checklist were said out loud as the climb check is or if we could take off with the bleeds on with low ceilings at a high elevation airport.

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Original NASA ASRS Text

Title: A DHC8's oxygen masks dropped at 12;500 FT after the bleeds were not OPEN because the Captain was distracted managing the wing deice boots and the cabin pressurization warning system failed.

Narrative: While departing on climb out we missed turning on the bleed air system. The weather was low overcast and the visibility was 1 mile. Our initial indication was a call from the Flight Attendant letting us know that the oxygen masks had deployed. This occurred climbing through 12;500 FT. Upon receiving this information we immediately turned on the bleed air system and checked that the aircraft was pressurizing properly. Our final cruise altitude was 13;000 FT. We continued the flight to our filed destination normally. Contributing factors that lead to our missing the bleed air system were: task saturation due to high elevation airport; weather; and Air Traffic Control frequency changes while on the IFR departure procedure; and the Master Warning Flasher to indicate a pressurization problem climbing through 10;000 FT not working properly. My Captain normally reaches to turn on the bleed air on his after takeoff flow. However; he needed to make sure that the de ice boots were on as we were climbing into icing conditions on this particular flight; thus interrupting his flow. At acceleration altitude we also changed from Tower to Center. I was flying the IFR departure procedure and my Captain was backing me up; as he should. Only having 3;000 FT to climb; he had not gotten to the climb check reaching 10;000 FT; which would have been another way to have caught that the cabin was not pressurizing before the oxygen masks dropped. We did not get a Master Warning Flasher indicating a pressurization issue. After the masks dropped; we discovered that some of the masks did not drop properly. Upon termination of the flight; the Oxygen masks; the oxygen masks that did not work properly; and the Master Warning Flasher were properly written up. A future event might be prevented if the after takeoff checklist were said out loud as the climb check is or If we could take off with the bleeds on with low ceilings at a high elevation airport.

Data retrieved from NASA's ASRS site as of July 2013 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.