Narrative:

After being instructed on a new; four truck deice procedure at a conference room with all involved in the deicing [procedure] (about 30); we were released and assigned to deice a B737-800 at gate C-11. It was already pushed back and waiting. I had my truck in position off the right-hand nose with mechanic Y in the pod above. Mechanic Y asked me on the intercom why mechanic Z was plugged in with a headset where we were to start [deicing] on the radome. I gestured to mechanic Z; but I believe he misinterpreted it. I asked mechanic Y if he'd like me to get out and ask. I'd been in neutral with my foot on the brake waiting to start; but another truck was having truck issues. I hopped out forgetting that I never had pulled the hand brake. I crossed in front of the truck; over the tow bar and grabbed mechanic Y's arm. He turned around and yelled when he saw the truck moving. I turned around and saw that it had hit the plane. It was very obvious to all around and inside the plane.I [previously] got my rig into our position; put it in neutral; and was waiting the word to start [de-icing] from the primary one truck. One of the trucks on the left-hand side reported truck issues with the pump I believe; so we sat for a while equipment ground support was called and next step was determined. The process was interrupted. I always set the hand brake if I ever hold in one spot long. I even set the brake while the wing is shot if it's a big job as in the ice. Everything was moving fast; as the plane was already pushed when we were assigned. Not that unusual in ice operations. I forgot that I had not set the brake.I ran up to the truck [after the truck hit the airplane]; opened the door and confirmed it was in neutral and the hand brake not set. I got in and another technician in front; hand signaled me to back up. I backed it up and the plane 'settled.' someone told me to see supervisor X; who took me to his office; told me to have a coffee; relax and come back. He did investigation paperwork and took me for my drug/alcohol test. After that I was released to work the schedule; not deice.like many accidents; things were out of the norm. A new [four truck] procedure; late notification; events not as trained (technician on headset at nose); deice truck broke down; holding in position longer than normal unplanned and simply forgetting to check the brake before getting out.

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Original NASA ASRS Text

Title: A Line Mechanic; after forgetting to set the hand brake; describes a chain of events that contributed to his de-icing truck rolling into the fuselage nose section of a company B737-800 aircraft.

Narrative: After being instructed on a new; four truck deice procedure at a conference room with all involved in the deicing [procedure] (about 30); we were released and assigned to deice a B737-800 at Gate C-11. It was already pushed back and waiting. I had my truck in position off the right-hand nose with Mechanic Y in the pod above. Mechanic Y asked me on the intercom why Mechanic Z was plugged in with a headset where we were to start [deicing] on the radome. I gestured to Mechanic Z; but I believe he misinterpreted it. I asked Mechanic Y if he'd like me to get out and ask. I'd been in neutral with my foot on the brake waiting to start; but another truck was having truck issues. I hopped out forgetting that I never had pulled the hand brake. I crossed in front of the truck; over the tow bar and grabbed Mechanic Y's arm. He turned around and yelled when he saw the truck moving. I turned around and saw that it had hit the plane. It was very obvious to all around and inside the plane.I [previously] got my rig into our position; put it in neutral; and was waiting the word to start [de-icing] from the primary one truck. One of the trucks on the left-hand side reported truck issues with the pump I believe; so we sat for a while Equipment Ground Support was called and next step was determined. The process was interrupted. I always set the hand brake if I ever hold in one spot long. I even set the brake while the wing is shot if it's a big job as in the ice. Everything was moving fast; as the plane was already pushed when we were assigned. Not that unusual in ice operations. I forgot that I had not set the brake.I ran up to the truck [after the truck hit the airplane]; opened the door and confirmed it was in neutral and the hand brake not set. I got in and another Technician in front; hand signaled me to back up. I backed it up and the plane 'settled.' Someone told me to see Supervisor X; who took me to his office; told me to have a coffee; relax and come back. He did investigation paperwork and took me for my drug/alcohol test. After that I was released to work the schedule; not deice.Like many accidents; things were out of the norm. A new [four truck] procedure; late notification; events not as trained (Technician on headset at nose); deice truck broke down; holding in position longer than normal unplanned and simply forgetting to check the brake before getting out.

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.