B737-700
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Commercial; Flight Crew Multiengine
Flight Crew Last 90 Days 390; Flight Crew Type 7826
Situational Awareness; Fatigue; Communication Breakdown; Confusion; Distraction; Time Pressure
Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance; Inflight Event / Encounter Fuel Issue
Flight Crew Became Reoriented
Procedure; Human Factors; Company Policy
I had flown seven out of the last nine days. This was the third leg on the last day of a four-day trip. Before push; the [weight and balance system] said we had a required 297 pound taxi burn to get to below ATOG. We elected to request Runway 25R so to burn the fuel on taxi out. The push took over 10 minutes from gate; due to a Trainee doing his first push. It involved a lot of stopping and starting and aggressive braking of the tug after we had both engines started.When we were finally ready to taxi; there was congestion. We realized that burning off fuel was no longer a problem; as a matter of fact; we were worried we were going to burn below our min takeoff fuel. We requested [Runway] 24L; and ran the Departure Plan Checklist. We taxied out to take our place in line. We were really watching our fuel burn at that point; as we were within 100 pounds of our min take off fuel. We were holding short behind a (other carrier) aircraft at the end of the runway when Tower cleared an aircraft to take off from the intersection behind us.I asked what our sequence was; and Tower did not reply. He then cleared (other carrier) to takeoff from in front of us. We were next cleared onto the runway. It was not until I read back 'cleared for takeoff' and the First Officer went to push the power up that he realized that the autothrottles were not armed and we had not run the checklist. I told Tower to cancel our clearance so that we could run the checklist. The checklist was completed and we took off. (Fuel was so tight on this one; that when we got to [destination]; we had to extend the gear just a bit early to burn down below max landing weight.)
B737-700 Captain reported forgetting to complete the Before Takeoff Checklist prior to taking the runway.