A long range air carrier flight crew were distracted by a main aircraft battery failure during engine start and attempted to taxi back to the gate without a release by their pushback crew. Minor contact with the towbar resulted.
Synopsis
A long range air carrier flight crew were distracted by a main aircraft battery failure during engine start and attempted to taxi back to the gate without a release by their pushback crew. Minor contact with the towbar resulted.
Narrative
We had an extended push back to an active taxiway. During push back; we discovered an electrical problem. We set brakes at the designated location; started engines and began a coordination with Maintenance Control to rectify the issue. The Captain kept the push crew hooked up to the aircraft while the electrical problem was investigated. I (the flying co-pilot) monitored Ground frequency while the Captain and Relief Pilot coordinated with Maintenance and ground personnel. We were told by Maintenance Control that a return to the gate was in order. I informed Ground of the need to return to a gate and they immediately gave us clearance and a gate. I relayed this information to the Captain and we released the brakes without coordinating with the ground crew. The airplane moved a short distance and struck the tow bar. We immediately reset the parking brake. The ground crew informed us of what happened and saw no damage. He reconnected the tow bar; we shut down engines and had the tug tow us back to the gate. The electrical problem (faulty main battery) was fixed and we continued with our flight.
Second reporter narrative
We noticed main battery discharge on push back; was not there prior.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.