B737-800
Flight Crew Air Transport Pilot (ATP)
Distraction
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Human Factors
Push back I told the ground crew 'brakes released; cleared to push'. But my brakes were not released and when I heard an unusual crunch noise; I realized that my brakes were not released. We stopped the push; called maintenance for a nose wheel inspection and made an Aircraft Maintenance Logbook entry. There was no damage to the airplane; but the tow bar was broken. We got a new tow bar and the flight continued.I said rote what I always say without verifying. I was distracted. I was concerned about the non revs not getting on the plane. The agent said there was a delay at security and they couldn't wait. She had a supervisor at the gate putting pressure on her. I was torn.Once I know that we are not going to wait for non revs; I need to leave it behind and put full attention to the procedures.
[Report narrative contained no additional information.]
B737-800 flight crew reported a push back with the brakes not released which broke the tow bar; after a new tow bar was installed; flight continued.