B737-400
Flight Crew Air Transport Pilot (ATP)
Distraction; Human-Machine Interface
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem
Aircraft; Human Factors
Our flight was about 30 minutes behind schedule and was departing an uncontrolled airport with a 7;000 foot runway. The weather was low overcast with a light direct crosswind. The First Officer was flying. We did not receive the clearance until after engine start. A new ATIS was published and obtained after start. We taxied to the west end of the airport then learned the new ATIS and FSS now suggested a runway change. I elected to enter the runway and back taxi to the opposite end of the runway. The takeoff brief and flight attendant alert were accomplished during the back taxi but the takeoff flap setting was missed in the taxi check and the flaps were set to up not five. During takeoff the First Officer set the power to about 49% pushed TOGA and the aircraft accelerated rapidly. The takeoff warning horn sounded and the Captain instinctively placed the flap lever to the 5 position and unintentionally hesitated the abort. The airspeed increased rapidly through 100 KTS and the flaps moved to the takeoff position. The flaps were nearing the takeoff position and the airspeed was increasing rapidly. The Captain made the decision to fly based on airspeed; flap position; and runway remaining. The flaps reached takeoff position well below rotation speed. A normal takeoff was accomplished followed by a normal flight.The Checklist was not accomplished correctly which caused the takeoff flap setting to be missed. The procedures were not followed correctly when the Captain hesitated on the abort.
Distracted by runway changes due to winds the flight crew of a B737-400 failed to select the planned flap setting prior to initiating the takeoff roll. When the takeoff warning horn sounded the Captain elected to select five degrees during the continued roll. The flaps reached the desired setting prior to rotation.