Narrative:

We were cleared to push from the gate to perform an experimental silent push procedure onto spot xx on taxiway M. When we were cleared to push from ramp; I inquired on the ramp frequency as to the operational requirements to push based on the memo I had read and what was given to us with the paperwork. I had not operated out of that gate for several months or maybe even a year and wanted clarification on certain details like dates of operation; etc. (There was not a mention of the pulling the plane up to the spot.) after asking the push crew if it was ok to release the brakes; I released the brakes; I commanded the push crew to push back to spot xx-Y. As we began to push; I monitored both radios for ground control to listen to the ground operations. I was trying to ascertain how long it would take for us to get off the ground in order to plan my taxi operations and engine start. As we neared the spot; I loaded the ZFW; vspeeds; and flex; while carefully reviewing each page of the takeoff data for accuracy. As we got closer to the spot; we received a call from the flight attendant stating the 'cabin was secure for takeoff.' as I commonly do; I focused on the speeds and takeoff data while I believe the first officer may have taken the interphone call. At approximately that same time; the aircraft came to what I thought was a complete stop. Also; at the exact same time; as the first officer spoke to the flight attendant on the interphone; or ground control; I was distracted when I looked down at my coffee cup and it was spilling on my charts during the pushback. I don't know if it was due to the push crew's technique of not smoothly pushing back; or if the lid had opened and started spilling onto my charts. So then I looked up at the first officer and muttered something like 'oh; crap; my charts...' and then the aircraft came to a complete stop. While the both radios were continuing to blast into my headset; and the flight attendant may have been talking to the first officer; I heard a mumble from the push crew. His wording was not very audible and nearly unreadable; but since I had heard it thousands of times before over the years; I heard/assumed that he said to set the brakes. So I did what he commanded me to do; and I set the brakes. I do not recall what exactly he said; but I thought it was to set the brakes which is what I was expecting him to do. At that instance; after pausing the push; he did not mention he was going to continue to pull me forward; and proceeded to pull the aircraft forward. It was at that instance that the sheer pin on the tow bar broke and a loud popping noise was heard and a sudden jolt. I looked down at the tug driver and he said 'oh no.' the first officer and I looked at each other and I asked 'what just happened?' the tug driver said 'the tow bar broke.' and we asked what happened down there? Is there any damage?' he said; 'no it looks ok; we just need to get another tow bar.' first officer and I looked at each other discussed what we should do. We both thought it would be better to just be safe. We asked them to pull us back into the gate and we would call maintenance in order to be safety conscious as to the possible damage done to the nosewheel and gear. I called maintenance to describe the event and wrote up the nose gear for possible damage. When maintenance came out; they immediately said it looked fine; and that we should be ok to continue. After further review; maintenance control decided to perform an aircraft swap and perform further inspections. We tried to be safety conscious at all times and erred on the side of caution; though the tug driver said it looked ok. I have never had an incident ever of any damage to an aircraft over the nearly 20 years of flying. There was organizational/operational pressure to get the flights out on time; with full loads. We felt we needed [to] complete the flights before the weather began to move into the area and cancel our later flights (losing revenuefor the company and pay for our crew.) the gate agent also was not comfortable with the boarding of this aircraft. We pushed back on time or even early; and felt the operational pressure to get the flight out and begin taxiing as the delays began to build up due to approaching weather.

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Original NASA ASRS Text

Title: During pushback; while utilizing a new procedure; the Captain misunderstood the ground crew and thought the pushback was complete; and set the brakes. When the ground crew attempted to move the aircraft forward to the intended parking spot; the tow bar shear pin broke. The aircraft was returned to the gate for a Maintenance Inspection.

Narrative: We were cleared to push from the gate to perform an experimental silent push procedure onto Spot XX on Taxiway M. When we were cleared to push from Ramp; I inquired on the Ramp Frequency as to the operational requirements to push based on the memo I had read and what was given to us with the paperwork. I had not operated out of that gate for several months or maybe even a year and wanted clarification on certain details like dates of operation; etc. (There was not a mention of the pulling the plane up to the spot.) After asking the push crew if it was ok to release the brakes; I released the brakes; I commanded the push crew to push back to Spot XX-Y. As we began to push; I monitored both radios for Ground Control to listen to the ground operations. I was trying to ascertain how long it would take for us to get off the ground in order to plan my taxi operations and engine start. As we neared the spot; I loaded the ZFW; Vspeeds; and Flex; while carefully reviewing each page of the Takeoff Data for accuracy. As we got closer to the spot; we received a call from the Flight Attendant stating the 'cabin was secure for takeoff.' As I commonly do; I focused on the speeds and Takeoff Data while I believe the First Officer may have taken the interphone call. At approximately that same time; the aircraft came to what I thought was a complete stop. Also; at the exact same time; as the First Officer spoke to the Flight Attendant on the interphone; or Ground Control; I was distracted when I looked down at my coffee cup and it was spilling on my charts during the pushback. I don't know if it was due to the push crew's technique of not smoothly pushing back; or if the lid had opened and started spilling onto my charts. So then I looked up at the First Officer and muttered something like 'Oh; crap; my charts...' and then the aircraft came to a complete stop. While the both radios were continuing to blast into my headset; and the Flight Attendant may have been talking to the First Officer; I heard a mumble from the push crew. His wording was not very audible and nearly unreadable; but since I had heard it thousands of times before over the years; I heard/assumed that he said to set the brakes. So I did what he commanded me to do; and I set the brakes. I do not recall what exactly he said; but I thought it was to set the brakes which is what I was expecting him to do. At that instance; after pausing the push; he did not mention he was going to continue to pull me forward; and proceeded to pull the aircraft forward. It was at that instance that the sheer pin on the tow bar broke and a loud popping noise was heard and a sudden jolt. I looked down at the tug driver and he said 'oh no.' The First Officer and I looked at each other and I asked 'what just happened?' The Tug driver said 'the tow bar broke.' And we asked what happened down there? Is there any damage?' He said; 'No it looks ok; we just need to get another tow bar.' First Officer and I looked at each other discussed what we should do. We both thought it would be better to just be safe. We asked them to pull us back into the gate and we would call Maintenance in order to be safety conscious as to the possible damage done to the nosewheel and gear. I called Maintenance to describe the event and wrote up the nose gear for possible damage. When Maintenance came out; they immediately said it looked fine; and that we should be ok to continue. After further review; Maintenance Control decided to perform an aircraft swap and perform further inspections. We tried to be safety conscious at all times and erred on the side of caution; though the tug driver said it looked ok. I have never had an incident ever of any damage to an aircraft over the nearly 20 years of flying. There was Organizational/Operational Pressure to get the flights out on time; with full loads. We felt we needed [to] complete the flights before the weather began to move into the area and cancel our later flights (losing revenuefor the company and pay for our crew.) The gate agent also was not comfortable with the boarding of this aircraft. We pushed back on time or even early; and felt the operational pressure to get the flight out and begin taxiing as the delays began to build up due to approaching weather.

Data retrieved from NASA's ASRS site as of July 2013 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.