B737-800
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 315
Situational Awareness; Communication Breakdown
Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Human Factors
Agent briefed us that we would be late due to connecting passengers and bag issues. Previously I had observed that the tug was connected to the aircraft and the nose wheels were chocked. At about departure time I chose to release the parking brake to be a 'Team' player and give the Agent an on time. About 15 minutes later and about 15 minutes after scheduled departure time the jet bridge was pulled.I observed that it seemed to be moving faster than normal and just did not feel right. At that point my First Officer stated 'we are rolling back'. I very gently applied the brakes and the aircraft stopped. We probably rolled five to ten feet back. Ground communication was established. I inquired if everyone was OK. They were. We were pulled back towards the jet bridge. We ran our procedures and departed uneventfully.Don't remove wheel chocks without letting the Flight Crew know.  Always have the tug brake set.
We began to run the Before Push Checklist. At some point during this time the Captain released the parking brake without notifying Ground Personnel; who were not around the aircraft at this time. We were then advised by the Agent that we were waiting to accommodate connecting passengers. While both of us pilots were heads down running the Before Push Checklist for a second time the chocks were removed. In each of our peripheral vision what we thought was the jetway moving away was; in fact; the jetway moving away as well as the aircraft rolling backwards. The Captain applied brakes as smoothly as possible; bringing the aircraft to a stop.The standard communication to the Ground Crew could have prevented this mishap in its entirety. As the First Officer; I should have made sure this communication was accomplished. The Ground Crew advising the pilots that the chocks were being removed could have also prevented this mishap; although I am aware that this is not normal operations.
B737-800 flight crew reported the aircraft rolled backward 5-10 feet after the ground crew removed the chocks not knowing the Captain had released the brakes without telling anyone.