Narrative:

During the push back the tug driver calmly stated; 'set brakes' since we were in the middle of an active pushback; I keyed the interphone mike to state/question; 'you want us to set brakes? You're still pushing us back!' simultaneously; I looked up to see that we had been inadvertently disconnected from the tow bar and were slowly drifting backwards. Because we were in the process of starting engine #1 and therefore producing a little forward thrust; our resultant backwards drift movement was fairly slow. Also; we were very fortunate that the tug driver made his brakes set request before his headset chord was ripped away (as it eventually was). Unfortunately; he did not state the proper term; 'breakaway' which would have alerted me of the real situation instead of my questioning his request to set brakes. This of course was alarming to all of us in the cockpit and on the ground. Once we got stopped without contacting any ground equipment or other aircraft traffic; the 'wing walker' re-connected his headset for communicating. I asked what happened and he apologized and stated that he was unsure why the tug disconnected as everything was properly attached before pushback. I told him it was important that he write-up his report and that I would do the same. I told him he was clear to disconnect his headset. He did and we then received the salute and release from guidance. After getting taxi clearance; it was apparent that the nose wheel steering was inoperative and I signaled the tug crew back to the airplane by cycling the taxi light multiple times. When he returned he apologized again stating that he forgot to remove the hydraulic bypass pin as the tow bar disconnection distracted him. He removed the pin and we got another salute and release from guidance for a normal taxi out.

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Original NASA ASRS Text

Title: An A320 broke loose from the pushback tractor and had to brake to a halt.

Narrative: During the push back the tug driver calmly stated; 'Set Brakes' Since we were in the middle of an active pushback; I keyed the interphone mike to state/question; 'You want us to set brakes? You're still pushing us back!' Simultaneously; I looked up to see that we had been inadvertently disconnected from the tow bar and were slowly drifting backwards. Because we were in the process of starting engine #1 and therefore producing a little forward thrust; our resultant backwards drift movement was fairly slow. Also; we were very fortunate that the tug driver made his brakes set request before his headset chord was ripped away (as it eventually was). Unfortunately; he did not state the proper term; 'Breakaway' which would have alerted me of the real situation instead of my questioning his request to set brakes. This of course was alarming to all of us in the cockpit and on the ground. Once we got stopped without contacting any ground equipment or other aircraft traffic; the 'wing walker' re-connected his headset for communicating. I asked what happened and he apologized and stated that he was unsure why the tug disconnected as everything was properly attached before pushback. I told him it was important that he write-up his report and that I would do the same. I told him he was clear to disconnect his headset. He did and we then received the salute and release from guidance. After getting taxi clearance; it was apparent that the nose wheel steering was inoperative and I signaled the tug crew back to the airplane by cycling the taxi light multiple times. When he returned he apologized again stating that he forgot to remove the hydraulic bypass pin as the tow bar disconnection distracted him. He removed the pin and we got another salute and release from guidance for a normal taxi out.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.