Narrative:

Push back clearance was received from ground control. The aircraft was already hooked up to the bar and tug and the driver seated with his headset on. I asked 'are you up' and received no response. I then gave the 'release brakes' hand sign and the driver came to life. We began a brisk push back and within a second or two I noticed the nose swing to the right while the tow bar was to the left of the nose; I had my hand on the emergency brake when the first officer said 'I think the tow bar is detached'. There was never any word from the driver; however; his expression showed he was aware of the malfunction. I was concentrating on slowly applying the brake as this was my third incident of this type. It did not matter; we came to a stop with the nose rising and returning to the ground. We had moved approximately one fuselage length and our tail was over the vehicle road. The ground crew then attempted to communicate with the cockpit with several headsets but were unable to do so. I do not know if the plug was damaged during the incident or inoperative before because the driver had not responded when I called him. We had used the headset earlier however. I then had the first officer advise ground of our position while I contacted maintenance for clearance to be towed back in. I was told to first inspect the nose wheel; if it had rotated 180 degrees towing was not authorized. I exited the cockpit; briefly explained the delay to the passengers; and saw the nose wheel had turned 180 degrees. I also inspected the tail skid and found it undamaged. I asked the supervisor if we were close enough to the terminal to deplane and was told 'yes'. I reentered the cabin; explained the problem; and instructed the passengers to deplane taking their carry ons with them. After they deplaned I asked the flight attendant if there were any injuries. She replied all were seated and belted and no injuries were reported. She; however; was standing and the motion was quite violent; passengers in the front row were reaching out to catch her.

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Original NASA ASRS Text

Title: When their towbar disconnected during pushback the flight crew of a Dash 8 had to brake to a halt while moving backwards; lifting the nose gear off the ground. While doing so the nose wheel rotated 180 degrees which disqualified the aircraft for either flight or towing prior to maintenance attention.

Narrative: Push back clearance was received from Ground Control. The aircraft was already hooked up to the bar and tug and the driver seated with his headset on. I asked 'are you up' and received no response. I then gave the 'release brakes' hand sign and the driver came to life. We began a brisk push back and within a second or two I noticed the nose swing to the right while the tow bar was to the left of the nose; I had my hand on the emergency brake when the First Officer said 'I think the tow bar is detached'. There was never any word from the driver; however; his expression showed he was aware of the malfunction. I was concentrating on slowly applying the brake as this was my third incident of this type. It did not matter; we came to a stop with the nose rising and returning to the ground. We had moved approximately one fuselage length and our tail was over the vehicle road. The ground crew then attempted to communicate with the cockpit with several headsets but were unable to do so. I do not know if the plug was damaged during the incident or inoperative before because the driver had not responded when I called him. We had used the headset earlier however. I then had the First Officer advise ground of our position while I contacted Maintenance for clearance to be towed back in. I was told to first inspect the nose wheel; if it had rotated 180 degrees towing was not authorized. I exited the cockpit; briefly explained the delay to the passengers; and saw the nose wheel had turned 180 degrees. I also inspected the tail skid and found it undamaged. I asked the supervisor if we were close enough to the terminal to deplane and was told 'yes'. I reentered the cabin; explained the problem; and instructed the passengers to deplane taking their carry ons with them. After they deplaned I asked the Flight Attendant if there were any injuries. She replied all were seated and belted and no injuries were reported. She; however; was standing and the motion was quite violent; passengers in the front row were reaching out to catch her.

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.