B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 198; Flight Crew Type 13300
Situational Awareness
Ground Event / Encounter Vehicle
General None Reported / Taken
Aircraft; Human Factors; Procedure
With all normal checklists complete and an early departure from the gate; immediately after brake release (on pushback) the tow bar apparently became disconnected from the tug; and the tug collided with the aircraft. Two or three loud bangs were heard and felt by the crew. I very quickly asked the driver what had happened and did not receive a response. My First Officer stated that the tug was sitting to the right side of the aircraft. I opened my cockpit window and yelled down to the ground crew and asked what had happened. The tug driver told me that the tug had malfunctioned. I informed him that I was going to reset the parking brake. I then completed a parking checklist; communicated with the crew; passengers; Operations; Dispatch; and Chief Pilot on duty.
[Report narrative contained no additional information.]
B737-700 flight crew reported that during pushback the tug became disconnected from the tow bar; and the tug collided with the aircraft.