B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 147; Flight Crew Type 4262
Workload; Distraction; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Procedure; Company Policy; Human Factors
Pushed back without weights. Multiple changes in taxi instructions. Single engine taxi. Radio congestion. Taxiway congestion. Runway change. Checklist interruption multiple times by ATC. Extremely busy operations.During taxi we missed the change in flap setting while completing checklist. We believe ATC called at the point of calling for flap configuration on 'before takeoff' checklist and it was missed. We set flaps correctly initially but failed to catch the change from 1 to 5 degrees. FMC was set up correctly but we missed changing flap position. Ramp said the right runway then changed by ATC to the left. On takeoff we noticed flaps were set wrong just before V1 and chose to continue by adding 10 knots to Vr and V2. Takeoff felt normal.
Pushed back without final weights. Person pushing us also confirmed that he had not [sent] in the numbers for final weights as we were pushing. Multiple changes in taxi instructions by Ramp and ATC. Told to hold short many times and also to keep a look out on traffic near us. Taxi out single-engine. Runway change while in the Ramp area on the move to the spot number. Multiple checklist interruptions by ATC. We set flaps initially at gate correctly for assumed runway per flight release. We failed to notice the flap change on the final takeoff request for the correct runway. We believe that the 'before takeoff' checklist was not clearly done correctly as we were interrupted by ATC. After airborne we both agreed that we failed to verify the flap setting for the correct runway. We noticed flaps were set wrong just prior to V1 and chose to continue by adding 10 knots to VR and V2. Take off was normal.
B737 flight crew reports taxiing without their final weights then receiving a runway change while doing single engine taxi. Very congested Ground Control frequency along with several hold instructions during taxi result in the before takeoff checklist not being completed. The result is a takeoff with the flaps set to 1 instead of 5 as required by the runway change.