Q400
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Confusion; Communication Breakdown; Time Pressure
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Vehicle
Aircraft Aircraft Damaged; General Flight Cancelled / Delayed; General Maintenance Action
Human Factors; Procedure
Pushback from spot A fifteen minutes late due to a late arrival.  Ramp control cleared us to push tail deep to allow spot B to push.  During the pushback the aircraft at spot B started their push.  The tug operator pushed deep but did not provide a lot of room for the aircraft pushing off of spot B.  I thought about asking the tug driver to push a little deeper but then I saw the aircraft pushing from spot B had already joining whisky and it looked like there was enough room so I didn't say anything.  About this time the aircraft came to a complete stop and I heard the tug driver say set brake.  I do not recall the exact exchange; whether he used the whole phraseology of 'pushback complete set brakes' or not.  The CVR should shed light on this.  At any rate I set the brake as instructed and just as I was saying 'brakes set' the tug lurched forward.   The aircraft jolted and came to a stop with the nosewheel on the tug.  When this happened; instinctively realizing what was happening and without thinking I released the park brake but it was too late the nose was already on the tug.  In hindsight I probably shouldn't have released the park brake but it was an unconscious reaction to what was happening and I didn't even realize I had released the brake until sometime afterwards when I noticed it was not engaged.  I reset it at that point to prevent the aircraft from moving.  Immediately following the accident I asked the tug driver if he was ok but there wasn't any response.  From this point forward I lost all ground communications with the ramp.  The tug driver looked ok from looking out the windshield.  The jolt wasn't strong enough to have hurt anyone on the airplane.  I asked my first officer if he heard the tug driver say set brake and he said yes.  The first officer told ramp control that we were stuck.  Several ground managers approached the airplane.  I couldn't communicate with any of them so I tried to call ops to try to get some information on what had happened.  I made a PA to the passengers and told them what had happened and that I would update them when I had more information.  At this point I didn't know the severity of the incident whether the tug could be removed or whether after a maintenance inspected the nosewheel the aircraft could be taxied back to the gate.After about a minute or two it became clear that we weren't going anywhere.  I started the APU and shutdown the engines.  I made a follow up PA to the passengers. Again because I couldn't communicate with anyone on the ground and because ops wasn't providing a lot of information I didn't know what was going on around the aircraft.  There were a lot of ops trucks and people taking photos with their cell phones.  I felt very much out of the loop.  I was hoping someone would open the door and come talk to me and let me know what was going on.  I didn't want to leave my seat because we were on an active taxiway.  Eventually someone did open the main cabin door and came and spoke with me and said the airplane would need to be jacked up to get the tug out and that the passengers would deplane out of the aft passenger door and board a bus to the terminal.  I made another PA telling the passengers the plan.  Half of the passengers deplaned and filled the bus.  Then the ramp unloaded the aft baggage compartment and then the second half of the passengers deplaned.  During this process I called dispatch; told them what happened and asked to talk to the duty officer.  The dispatcher said the duty officer was aware of what was going on and would catch up with me soon.  [The duty officer] called right after that conversation.  I told him what I thought happened and I suggested that the CRV be preserved.  He agreed that I could pull the CRV circuit breaker to preserve the tapes.  He told me what I needed to do (drug tests; paperwork; meetings) and would be moving forward.After all the passengers were off the airplane I made a log book entry and turned the plane over to maintenance.  There was a flight deck jumpseater on this flight.  Later in the terminal I asked him what he remembered hearing on the pushback but he said he couldn't recall any of the exchanges.  I took down his phone number and he agreed to make a statement if necessary.Maybe lack of proper and clear phraseology; but since I can't recall all the exact words exchanged this may or may not be a cause.  I'm not 100 percent certain but I think that after the driver said set brakes; he looked behind him at the aircraft pushing from spot B.  I think when the tug lurched forward he was actually looking behind him and not forward.  I think the nosewheel went higher on the tug than it should have because of this reason.  He was looking behind him at the time and didn't initially realize what was going on.  I suspect that he accidentally pushed the gas petal while looking behind him or he decided the aircraft was too close and decided to push deeper forgetting he told me to set the brake.  Alternatively I could have misheard him; and he said something else other than set brake.  Again the CRV should clear this up. Video surveillance may also be a good tool to help see what was going on at the time.
The beginning of the push back out of the gate was normal. Ramp control instructed us to push tail north and deep to allow company south of us push as well. We started Engine 1 at the gate and 2 on the push. During the push everything was normal and I was watching after I started the engine to ensure the tug operator pushed us deep enough north. I noticed that company was kind of close to us in proximity in the push now in front of us. I think the tug driver attempted to stop then said a garbled word followed by 'Brake'; then realized the proximity of the aircraft in front of us and kept the push going. The Captain set the Emergency brake at the word brake; and from what I recollect we were still moving. The nose wheel left the cradle of the tug and ended up on top of it. I could see the horror in the tug operator's eyes. The first thing the Captain asked the tug driver if he was ok; though communication had been lost from the headset connection. We then started the APU and shut down both engines. We advised ATC of the situation and continued to monitor Apron. Later a bus was brought out to take the passengers back to the terminal. No one was injured due to this event to my knowledge. The cause of this event is the complacency from both ground crew and Captain. Tug operator should have never said 'Brake' and the Captain should have not been so quick to set brake. I believe this incident could have been avoided if we removed the headset communication from ramp to flight deck and returned to the Basics of hand signals. That way the tug driver would have been required to remove hands from the steering wheel to show set brakes signal; and flight crew would have to look up to acknowledge the signal before setting the brakes.
During pushback a breakdown in communication resulted in the Q400 Captain setting the parking brake and at some point the tug continuing to push. The aircraft nose wheel ended up on top of the tug.