B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 250; Flight Crew Type 2395
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Human Factors
After takeoff the Cabin Altitude Warning sounded passing 10000 MSL. During preflight we requested and received takeoff data for a Flaps 5 Bleeds ON takeoff. During taxi out we received an error twice when attempting to get final takeoff data for Flaps 5 Bleeds ON. This seemed a little unusual since our takeoff weight had decreased from the planned weight. We then requested and received takeoff data for a Flaps 5 Bleeds OFF takeoff.While holding number 1 for takeoff we told tower we needed a few minutes to complete our checklists. We then reconfigured the Bleeds panel for a Bleeds Off takeoff and completed the Before Takeoff checklist. At this point neither of us remembered that we needed to start the APU which had been shut down after engine start.After takeoff I noticed the Cabin was climbing quickly and placed the Right bleed switch on and configure the bleed panel for normal operations. The Cabin Alt Warning horn sounded briefly and the cabin descended immediately back below 10000 ft.
[Report narrative contained no additional information.]
B737 flight crew reported a bleeds off takeoff from a high altitude airport with the APU shut down which resulted in the cabin altitude warning sounding at 10;000 feet.