Flight Crew Air Transport Pilot (ATP)
Confusion; Distraction; Situational Awareness; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown; Ground Event / Encounter Other / Unknown
Aircraft Aircraft Damaged; Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Human Factors; Aircraft; Procedure
After pushback from the gate area- the tug operator had difficulty getting the tug to back away from the aircraft due to the angle between the tug and aircraft nose wheels. Eventually other tug operators assisted and after several attempts the aircraft and the tug would not separate due to the position of the nose wheel on the tug's ramp.The tug operator asked me to turn on the steering in order to turn the nose-wheel (this was to assist them with getting the tug separated) however I told them I could not do that with them standing there. Maintenance personnel arrived and via headphones asked me to turn on the steering and they assured me all ground people were clear of the aircraft.  The steering would not work.  The nose wheel was stuck or locked into one position and would not move.  After several attempts by maintenance the tug was able to back away from the aircraft however there was no steering.  The decision was made to return to gate using a tug.  However this did not work out because the nose wheel would not turn and eventually the sheer-pin for the tow-bar broke.  A second attempt to tow the aircraft (aft to a closer parking area) caused the second sheer-pin to break too.  At this time I told all personnel that we will put deplaning of passenger as the number one priority and only after the passengers leave will we resume dealing with the aircraft.  The Port did get a bus to us; all passengers and their bags were transported away from the aircraft and back to the terminal.  A third attempt to tow the aircraft; with just the crew onboard; was successful and the aircraft was parked at the gate.During this event the Flight Attendants kept the passengers informed; provided water and snacks; and coordinated getting everyone (in need) up to the bathroom. The First Officer provide excellent advice; PAs and his help was invaluable. I attempted to make several PAs too- in order to keep the passengers informed of our status.While I believed the nose-wheel steering system was selected to OFF during pushback; it appears that it was actually ON.  I suspect I am responsible for inadvertently turning on the system and not being aware.  This resulted in damage to the steering system. This is the only plausible reason; at this time; which I believe could cause this to happen.
A Q400 Captain apparently left the nose wheel steering powered during pushback which resulted in the ground crew's inability to disconnect the tow bar. The aircraft returned to gate for maintenance.