Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 240
Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Aircraft
Aircraft Aircraft Damaged
Procedure; Human Factors; Company Policy
Aircraft was cleared to push from gate. ATC asked us to push deep behind [adjacent] gate to allow for aircraft to enter our gate.  Pushback Crew completed 90 degrees pushing turn. I noticed the aircraft had gone beyond 90 degrees and was deviating from the taxi line at almost the same moment the aircraft shook and came to a stop. I aborted the number one engine start at that moment and shut down the number two engine moments later. After stopping; the tug driver stated that he might have hit something; but from the cockpit we had no visibility of the impact. We were told that in fact we had collided with the parked aircraft at [adjacent] gate. The decision was made not to move the aircraft and the Passengers were deplaned on the taxiway after coordinating with airport operations. I was not aware whether this was a three person push; but it seems that if a 90 degree turn is required than the push crew should always have two wing walkers.
[Report narrative contained no additional information.]
During pushback aircraft struck an aircraft on an adjacent gate.