Air carrier flight crew reported they did not set the parking brake after taxiing into the gate and the aircraft rolled backwards.
Synopsis
Air carrier flight crew reported they did not set the parking brake after taxiing into the gate and the aircraft rolled backwards.
Narrative
Aircraft was pulled into gate XX at ZZZ. Once stopped per ramp guidance; CA went into Shutdown flow and shutdown engines. FO (myself) completed shutdown flow and prepared for shutdown checklist. First item on C/L is parking brake verification. That's when CA realized the brake had not completely set and was off. During this time; aircraft had rolled backwards. When CA/FO noticed the brake; CA immediately set the brake and the aircraft lurched suddenly to a stop. Aircraft had to be restarted and taxied forward so jetbridge could be connected. Bridge was still off the aircraft at the time this occurred. Passengers were seated; ENG (Engine) 1 was restarted via coordination with ground crew; and aircraft was taxied back into position. CA and FO debried the issue and spoke to FAs. No injuries or damage were reported. Cause: Failure to set parking brake completely led to the aircraft rolling backwards.Suggestions: Verification of parking brake being set before foot brakes are released. Better SA (Situational Awareness) by crew to identify aircraft movement.
Second reporter narrative
Today; while parking at Gate XX in ZZZ; I applied the parking brake during my shutdown flow. However; it apparently was not completely set. I noticed it was not set during the shutdown checklist. I set the brake immediately. The aircraft had rolled back about 1 foot. The aircraft stopped abruptly.The crew chief asked me to restart ENG (Engine) 1 and taxi it back forward. After checking with the flight attendants and notifying our passengers; I restarted eng1 and moved the plane back up to the correct spot.Fortunately; no injuries occurred inside or outside the aircraft. I followed up with the dispatcher; flight crew and crew chief. I will follow up with a pilot debrief as well.Cause: My visual attention was outside the aircraft watching the crew chief when I set the brake. I should have visually verified the parking brake position AND lighted indication before releasing the toe brakes.Suggestions: For me; I should have visually verified my flow. Fortunately; the checklist caught my error.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.