Date: 202106
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Dawn
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb; Initial Climb
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Escape Slide
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Situational Awareness; Troubleshooting
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Aircraft Aircraft Damaged; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; Flight Crew Landed in Emergency Condition; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: [The] flight departed ZZZ; [runway] XXL and at 400 ft. we were given a heading of 360. As soon as the turn was initiated a loud bang was heard from below and behind the cockpit. The noise then went away. A few moments later FA (Flight Attendant) 1 called up and reported a loud banging noise from 2R. There were no ECAM or any other indications in the cockpit - all displays were normal - nor was the noise audible from the cockpit. After getting the airplane stabilized and the after-takeoff checks completed; I sent the FO (First Officer) back to investigate. It was confirmed that a loud banging was obvious in the cabin. A return to the field was planned; ATC notified; [priority handling was requested]; FA's briefed for a precautionary landing; Dispatch notified and CFR (Crash Fire Rescue) requested. Runway XY was requested as this was an overweight landing; and the QRH procedure was followed. A smooth landing followed; the aircraft was brought to a stop after clearing Runway XY and the airplane inspected by CFR crew. The comment was that; 'A door was missing.' No other damage noted; and the flight taxied to a gate uneventfully. A walk-around revealed the 2R slide door departed the aircraft; followed by the slide. The noise was from the inflation supply line which was banging against the fuselage and wing root. A write-up for the missing door and raft was entered into the log along with the overweight landing notes. [The cause can be found through] perhaps confirmation of all maintenance items accomplished during the inspection at ZZZ immediately previous to this event. [I suggest to find the] determination of why the slide/raft door failed and [to find] appropriate remedies [to be] taken to preclude future issues.


Second narrative: I was assigned FO (First Officer) on [the] flight. I arrived at aircraft and the Captain was already at the aircraft. I performed the preflight walk-around and noted no issues. All checks for preflight were normal. We were cleared for takeoff on Runway XXL; initial climb to 5000 and heading 290. Takeoff was normal. The Captain called for AP (Autopilot) on and pulled heading at turn altitude. Climb power reduction and clean-up was normal. We were handed off to Departure and checked in. Departure gave us a climb to 7;000 and 360 heading. I confirmed 7;000 with ATC and the Captain set 7;000 and I confirmed it. As he turned the heading knob to 360; a loud bang was heard from behind the flight deck. The #1 FA (Flight Attendant) called and reported the bang and a clunking noise near 2R door. No ECAM or warnings were displayed.The Captain retained the aircraft; leveled at 16;000 as cleared; and set speed to 245. We completed all checks and asked ATC to remain at 16000 as we needed to check out something. They approved that and asked if we were [requesting priority handling]. We replied not at this time; but we will need to check some things. The Captain then asked if I was OK with going back and checking things out as the sound could not be heard on the flight deck. The FA came forward and I went to the cabin and inspected the area and heard the banging she described. I returned to the flight deck; described what I heard and what I felt was happening and suggested that we return. The Captain agreed and formulated a return plan. He completed all notifications [and] reviewed all procedures with me. We [requested priority handling] and returned to base for an overweight landing.The Captain performed the landing as per QRH procedures. He brought the aircraft to a stop on the taxiway as CFR (Crash Fire Rescue) could inspect the aircraft; and they informed us that there was a door open and everything else looked OK. We taxied to the gate; followed shutdown procedures; and then went down to inspect the aircraft. At that time; we found that the 2R slide door and slide were missing and the inflation hose was hanging down and had struck the fuselage. The Captain the entered entries in the AML for the damage and overweight landing.My concern is that when we checked the system pages to see if we had any systems issues; there were none indicated. The doors page showed all the slides green and the white 'slide' indications. I.e.; normal armed condition. Had the green box that indicated the 2R slide shown amber; we would have been alerted that the door was in fact open - in this case gone - and would have had a better idea of what we were dealing with.


Synopsis: A321 flight crew reported a loud bang followed by repetitive banging aft of the cockpit door and elected to perform an air turnback where it was discovered that a slide and slide door had departed the aircraft.