Date: 202106
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Aircraft component: Parking Brake
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Communication Breakdown; Distraction; Situational Awareness; Training / Qualification; Workload
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Loss Of Aircraft Control; Ground Event / Encounter Object
Detector: Person Ground Personnel
When detected: Aircraft In Service At Gate
Result: Aircraft Aircraft Damaged; General Maintenance Action
Contributing factors: Human Factors; Procedure; Staffing; Aircraft
Primary problem: Human Factors

Narrative: We arrived at ZZZ Gate at approximately XA:30. Upon arriving at the gate there were no ramp personnel in the area. We parked as directed by the DGS system; shut down the engines; and performed the Shutdown Checklist (including 'Brakes Set'). After a few minutes; (indicated by the cargo doors opening on the ECAM) ground personnel approached the aircraft to perform their duties. I left my seat to use the lavatory and to assure the #1 Flight Attendant (FA) and our First Class passengers that we were diligently trying to find someone to open the door. Approximately 10-15 minutes later; the agent opened the door. I returned to the flight deck to gather my belongings before saying goodbye to the passengers at the door. We never received the 'chocks in' hand signal and had no ground power connected despite our efforts to get it done. In the mean time; shortly after main cabin door opening; a maintenance tech came up to the flight deck and gathered some pins from the gear pin stowage compartment; for what he indicated was some sort of inspection. I was called the next morning and informed by the ZZZ1 Director of Flight that while we were on the flight deck we had an aircraft rollback causing damage to the jet bridge. Not one person on or near the aircraft indicated that we had any aircraft movement and First Officer (FO) and I were totally unaware of the rollback. Often we arrive at the gate and there are no ramp personnel to chock the airplane. In addition; very shortly after door opening; there is a maintenance technician present to perform required operational inspections. As the flight deck crew; we performed our required post flight duties. We cannot account for the other several departments involved in the safe securing of the aircraft. As the Pilot-in-Command (PIC) of the aircraft; I sincerely believe that the parking brake was set. Given the intense scheduling practices and understaffing of the airline on the Aircraft Maintenance Department and Customer Service; along with the obvious poor training of Ground Support; I have no idea what happened.




Synopsis: A321 Captain reported being informed that the aircraft they arrived on rolled back and suffered ground damage after a collision with the jet bridge; which was also damaged.