A B737-700 flight crew failed to note both engine bleed switches were off despite running predepartu...

Attributes
ACN	997739
Time
Date	201203
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Pneumatic Valve/Bleed Valve
Person 1
Function	First Officer Pilot Flying
Experience	Flight Crew Last 90 Days 215 Flight Crew Type 1500
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 205
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Other / Unknown

Narrative:

The engine bleed switches were in the off position for takeoff. Somehow we missed it on the before takeoff checklist. While running the climb checklist at 10;000 MSL; we noticed the plane was not pressurizing; and started a level-off. At approximately 11;000 MSL; we got the cabin altitude warning horn. We leveled off; put on oxygen masks; and informed ATC we needed to descend to 10;000 MSL and they approved. We leveled at 10;000 MSL and the horn stopped. We then ran the abnormal pressurization; cabin altitude warning horn checklist; and realized both engine bleed switches were off. One at a time; per the checklist; we turned the engine bleed switches on and the plane pressurized. We checked with the flight attendants to make sure the oxygen masks in the back did not drop; and that no one in the back was having any issues. They informed us that everybody and everything in the back was fine. We coordinated with ATC and continued. We sent a message to dispatch with a brief description and our intentions to continue. The rest of the flight was uneventful. We did run all the normal checklists but did not properly crosscheck with our responses. It was not a planned bleeds off takeoff. I don't know for sure when the engine bleeds were placed in the off position. Proper preflight and better attention to the crosscheck during checklist challenge and response would have prevented this from happening.

Original NASA ASRS Text

Title: A B737-700 flight crew failed to note both Engine Bleed switches were off despite running predeparture checklists which required them to be in the on position. The error was discovered and corrected when the cabin altitude warning horn sounded.

Narrative: The Engine Bleed switches were in the off position for takeoff. Somehow we missed it on the Before Takeoff Checklist. While running the Climb Checklist at 10;000 MSL; we noticed the plane was not pressurizing; and started a level-off. At approximately 11;000 MSL; we got the Cabin Altitude Warning Horn. We leveled off; put on oxygen masks; and informed ATC we needed to descend to 10;000 MSL and they approved. We leveled at 10;000 MSL and the horn stopped. We then ran the Abnormal Pressurization; Cabin Altitude Warning Horn Checklist; and realized both Engine Bleed switches were off. One at a time; per the checklist; we turned the Engine Bleed switches on and the plane pressurized. We checked with the flight attendants to make sure the oxygen masks in the back did not drop; and that no one in the back was having any issues. They informed us that everybody and everything in the back was fine. We coordinated with ATC and continued. We sent a message to Dispatch with a brief description and our intentions to continue. The rest of the flight was uneventful. We did run all the normal checklists but did not properly crosscheck with our responses. It was not a planned bleeds off takeoff. I don't know for sure when the engine bleeds were placed in the off position. Proper preflight and better attention to the crosscheck during checklist challenge and response would have prevented this from happening.

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.

A B737-700 flight crew failed to note both engine bleed switches were off despite running predeparture checklists which required them to be in the on position. The error was discovered and corrected when the cabin altitude warning horn sounded.