Narrative:

Around 10;000 ft on the climbout; the #1 flight attendant called to tell us that the cabin was warm; there was an exhaust smell and his ears were popping. A few seconds later we got a cabin altitude warning horn. The captain was the first to put on his mask. I stopped the climbing and then donned mine. I was very busy trying to maneuver the aircraft smoothly with the autopilot off and did not immediately establish communications. The captain advised ATC that we had a pressurization problem and needed to descend. I turned the pressurization mode control switch to man and turned the valve switched to closed. Next I set up the flight intercom and advised the captain of my actions. We requested 8;000 ft and a return. When everything was stable; the captain noticed the engine bleed switches were in the off position. We turned the switches on and pressurization mode controller to automatic. The aircraft began to pressurize normally. We discussed the fuel status and determined that; from a safety standpoint; there was no obstacles in continuing. We advised ATC of our status and requested on course. We were then cleared en route and continued the flight with no further interruptions. From my perspective; contributing factors in this event were a poor nights sleep and a last minute change of power from standard thrust to 22;000 maximum due to a tailwind component of about 1 knot. I think if I didn't have that power change on my mind I may have noticed the different feel of the pressurization on takeoff. The #1 flight attendant was sharp to notify us of the unusual temperature and smell in the cabin. I don't know at what point the engine bleed valves were switched to off or if they were never switched on. The fact that I didn't catch them with the checklist is troubling and will require a good deal of thought and much more vigilance in order to avoid similar problems in the future. It may be worth mentioning that the cabin altitude warning horn went off until the cabin came back to below 10;000 ft. We train to silence the bell when we get a fire warning but it isn't usually discussed for a cabin altitude warning. It didn't occur to me to silence it until it was too late but would have been helpful.

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Original NASA ASRS Text

Title: A B737-800 flight crew reported taking off with the Bleed Air Switches CLOSED and above 10;000 FT the cabin altitude warning horn sounded. An emergency declaration was canceled and the flight continued to its destination after the bleed switches were OPENED.

Narrative: Around 10;000 FT on the climbout; the #1 Flight Attendant called to tell us that the cabin was warm; there was an exhaust smell and his ears were popping. A few seconds later we got a cabin altitude warning horn. The Captain was the first to put on his mask. I stopped the climbing and then donned mine. I was very busy trying to maneuver the aircraft smoothly with the autopilot off and did not immediately establish communications. The Captain advised ATC that we had a pressurization problem and needed to descend. I turned the Pressurization Mode Control switch to MAN and turned the valve switched to CLOSED. Next I set up the flight intercom and advised the Captain of my actions. We requested 8;000 FT and a return. When everything was stable; the Captain noticed the Engine Bleed switches were in the OFF position. We turned the switches ON and Pressurization Mode Controller to AUTO. The aircraft began to pressurize normally. We discussed the fuel status and determined that; from a safety standpoint; there was no obstacles in continuing. We advised ATC of our status and requested on course. We were then cleared en route and continued the flight with no further interruptions. From my perspective; contributing factors in this event were a poor nights sleep and a last minute change of power from standard thrust to 22;000 maximum due to a tailwind component of about 1 knot. I think if I didn't have that power change on my mind I may have noticed the different feel of the pressurization on takeoff. The #1 Flight Attendant was sharp to notify us of the unusual temperature and smell in the cabin. I don't know at what point the engine bleed valves were switched to off or if they were never switched on. The fact that I didn't catch them with the checklist is troubling and will require a good deal of thought and much more vigilance in order to avoid similar problems in the future. It may be worth mentioning that the Cabin Altitude Warning horn went off until the cabin came back to below 10;000 FT. We train to silence the bell when we get a fire warning but it isn't usually discussed for a Cabin Altitude Warning. It didn't occur to me to silence it until it was too late but would have been helpful.

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.