Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; MEL; Procedure; Manuals
On day one of a four day trip; I was advised [later] on to provide information about [a] flights performed a few days prior. Today; at the conclusion of that trip; is the first opportunity to file this report.[The] flight was scheduled ZZZ to ZZZ1. On initial climbout; the aircraft presented ECAM - VENT SKIN EXTRACT VALVE FAULT. I was Pilot Monitoring. The Captain asked me to run the ECAM. As I preceded; the procedure was leading me to put the aircraft into an unpressurized configuration. We discussed the problem and decided to return to ZZZ because we would not have the fuel required to get to ZZZ1 at 10;000 feet and ZZZ was the closest airport in point of time. We were under max landing weight and therefore preformed a normal landing and taxi in to an available gate.At the gate; the Captain wrote the discrepancy into the maintenance log. Maintenance decided they could apply an MEL. Once the MEL procedures where complete; we expected to retry our flight to ZZZ1. Once refueled and signed off by Maintenance; we departed on our second attempt.After our second takeoff; there was an appreciable high wind noise level that we both commented on as different from our first flight and as being very unusual. As per the MEL procedure we expected the same ECAM; got it; and cancelled it as per procedure. As we climbed however; I noticed that the cabin was climbing higher than normal and higher than what I would have expected. We decided to continue to monitor the cabin pressure. Passing approximately 15;000 feet altitude; as we monitored the cabin altitude; we heard a pop; followed by a significant increase in the cockpit wind noise and saw and felt the cabin climbing significantly high at approximately 3;000 feet per minute. We requested priority handling and requested a descent to 10;000 feet. Cabin altitude reached 12;500 feet at its highest point; before we could reverse the cabin climb in our decent. Once under 10;000 feet; crew O2 was no longer needed; passenger O2 had not deployed and passengers no longer needed O2. We were again below max landing weight; so we returned to ZZZ; performed a normal landing; and taxied into an available gate. Maintenance personnel took the airplane to the hangar.Maintenance may have wired open the wrong door. Otherwise; there could have been an additional failure in the system. I can only speculate on a cause for the events of these flights; because I have been given no further details on the aircraft's maintenance. The Captain and I reacted to the situation as best as we could; trying to interpret the information being presented to us as quickly as we could. If we could have determined sooner that the cabin pressurization would fail; we may have been able to avoid an emergency descent.
A321 First Officer reported performing two air turn backs that were caused by a malfunctioning Cabin Pressure Control System.