Air carrier flight crew reported while at the gate having a miscommunication with the ground crew resulting in the aircraft rolling backwards. The flight crew was able to apply the brakes and regained control of the aircraft.
Synopsis
Air carrier flight crew reported while at the gate having a miscommunication with the ground crew resulting in the aircraft rolling backwards. The flight crew was able to apply the brakes and regained control of the aircraft.
Narrative
At the gate in ZZZ; we were preparing for our departure to ZZZ1 as usual. We had completed our checks; reviewed the flight plan; and briefed the flight. While waiting for the data to be received; I was trying to finish my lunch. Once we got the data; I told the flight attendants that they were good to close. My First Officer and I were then working on entering the final data into the FMS. While entering the data into the FMS; we established communications with the ground crew; and released the brake. Then I heard the ramper saying he was pulling a chock and immediately after had alerted that we were rolling. Then I applied the parking brake and turned on our hydraulic pumps to have brake pressure. The ramper advised no damages; and that his managers were going to come to evaluate the situation. I talked to Dispatch; Maintenance Control; and ran the event through them. Maintenance Control had advised that the plane was good to go; as well as local contract Maintenance. After that we pushed back and departed without further incident. Cause: The cause for the plane to roll back; was the chocks being removed and the brake released without being hooked to the tug. I thought that I had heard the ramper say the standard phrases; and say he was ready for the brakes; I think that I may have misheard him. I was working to get the FMS set up; and get ready for the before start checklist. My sandwich was leaking sauce all over; and I allowed myself to be distracted.Suggestions: I will work to not allow myself to be distracted as I was; and I will definitely slow down; and communicate better. I shouldn't have tried to multitask and I should have completed one task at a time.
Second reporter narrative
I finished the walk around and went back into the flight deck. I setup my iPad and completed the flight deck prep flow. I got our clearance via PDC and entered the route into the FMS. The Captain and I did our route review and takeoff briefing. While I waited for the numbers to come through I heard the Captain and rampers talk. While I was finalizing the FMS I looked up and saw we were slowly rolling backwards. At the same time one of the rampers called 'brakes; brakes; brakes'. I saw my Captain pull the parking brake and turn on the hydraulic pumps. At the same time I saw this I applied pressure on the tow brakes. After getting the aircraft to stop Maintenance was called to come inspect the aircraft. Both ZZZ2 Maintenance and the local mechanic in ZZZ said the aircraft was good to fly. A new ramp crew was brought in and we pushed back. The flight continued normally from there.Cause: Having the chocks removed without the brakes engaged or the tug hooked up.Suggestions: Slow down and verify that the brakes are engaged or the tug is attached before having the chocks removed.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.