A319
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 10514; Flight Crew Type 8252
Fatigue; Distraction; Communication Breakdown; Confusion
Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown; Ground Event / Encounter Loss Of Aircraft Control
Flight Crew Became Reoriented; Flight Crew Regained Aircraft Control
Human Factors
Upon arrival at gate single engine; ran out momentum just prior to parking spot and had to add a little power. Marshaller gave stop signal shortly thereafter and stopped normally using toe brakes. For some reason I failed to set parking brake; and the aircraft begin rolling backwards. I stopped the airplane; set the parking brake; and the aircraft was later towed forward into position.I don't not have an answer for why I failed to set the brake. I believe it was a combination of being tired from four days of flying; a very early wake up; thinking about using a new parking checklist for the first time; but overall; just a lack of concentration and focus. No excuse. All were red flags that should have been heeded and resulted in greater focus and concentration. The flight is not over until the parking checklist is complete and our passengers are off the airplane. We all must remember that. I certainly will.It is very easy to become complacent in this business of repetitive flights to the same stations; multiple legs each day; etc. We absolutely cannot let this happen as it will bite us when we least expect it; such as this; the last event of the last leg of the last day of a four day trip. 'It ain't over until it's over' Good advice from a wise former baseball player. I certainly won't forget it.
I was parking this plane. Once I had it parked; I went to grab the chocks for the nose gear. When I turned around the plane was rolling back.
A319 Captain and Ramp Marshaller reported the aircraft began to roll back after parking short of gate. Captain inadvertently failed to set parking brake when commanded by ramp personnel. Captain then set parking brake.