Flight crew reported on departure a problem with the PACK 1-2 Valve Closed and returned to departure airport.
Synopsis
Flight crew reported on departure a problem with the PACK 1-2 Valve Closed and returned to departure airport.
Narrative
ZZZ to ZZZ1. Pack 1 was differed PACK 1 VLV CLSD EICAS (Engine Indicating and Crew Alerting System) displayed per MEL. During the climb check I saw the message PACK1-2 VLV CLSD and saw the cabin wasn't pressurizing. I cycled Pack 2. Pack 2 turned back on; cabin began to pressurize for around 60 seconds and then back off. The PACK 1-2 VLV CLSD message came back and the cabin was not pressurizing. And 9;500 ft. MSL; I ran the QRH for PACK 2 valve closed and it instructed me to cycle the pack so I did so. The pack turned on and the cabin started to pressurize. Around 10;500 ft. MSL PACK 2 turned again. I notified ATC we had a pressurization issue and needed to descend to 10;000 ft. MSL. Cabin altitude reached a max of 10;200 ft. before we leveled off at 10;000 ft. MSL. I messaged Dispatch informing them of the situation and was instructed to return to ZZZ. We notified ATC needed to burn fuel before returning. We initially received vectors and were eventually put into a hold over ZZZ2. Once we burned sufficient fuel we continued to ZZZ1. Prior to the flight we had a last minute FO (First Officer) change. We did not get an amended release but both pilots signed the release. Per [operating manual]; an amended release is only required for a PIC (Pilot in Command) change. Do not allow an airplane to fly out of a base with company maintenance with an inoperative pack.
Second reporter narrative
I was put on the flight roughly 15 minutes before departure due to another FO (First Officer) having a miscommunication. Upon showing up for the flight I and the Captain discussed the MEL of Pack 1 and how it affected the flight. The release had the former FO and the Captain flying per [operating manual] it says release must only be amended for change of PIC (Pilot in Command) and tail so I signed the release through my daily. Upon taking off through roughly 10;000 ft. MSL the Pack 1-2 closed message came up. The Captain cycled the pack and the airplane began to pressurize normally the failure then happened again at roughly 11;500 ft. at which point I slowed our descent to 500 FPM and the captain went to the QRH and started to read the procedure. Coming through 13;000 ft. the pack was still failed and the cabin pressure was amber at 10;000 ft. cabin alt. We advised ATC we needed 10;000 ft. per the QRH and we descended safely but quickly. At this point we were overweight and asked for a box pattern from ATC while we called Company and Flight Attendant/passengers. We ran our max landing weight - the zero fuel weight and determined the number needed to land underweight. At this point the company advised us to return to ZZZ. We held for roughly 45 minutes and then came back to ZZZ after a normal landing was assured.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.