EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport
Aircraft
On takeoff the airplane did not pressurize with both PACKS ON; Cross-bleed Open; and APU bleed OPEN. During the takeoff roll I noticed that the plane felt a little different; it even made me double check that my window was not open. However; I did not look down to notice on the bottom of the EICAS that the PSI was 0. During the After Takeoff Flow and checklist the CA (Captain) and I noticed that the Cabin Rate was 2000 FPM; as was the aircraft climb rate; and the PSI was 0. We were cleared to climb to 10;000 feet but requested a level off at 5000 feet I believe. I directed the CA to look for an appropriate QRH; but because we received no EICAS message; that required using the un-annunciated index. We ended up using the Pressurization Auto System Failure/Cabin Depressurization/Cabin Rate Abnormal fluctuations checklist. I was not 100% certain this was the appropriate checklist. Besides the items on the checklist; we recycled the PACKS and put the APU bleed open with engine bleeds closed to see if that would fix the problem. When we put the pressurization controller to the 11 o'clock position with the mode selector in manual; the cabin immediately started rapidly descending; as much as 3000 FPM.  Because the rate was going down while we were level; we decided to go up a little higher to see if the system was working. We climbed up to 8000 feet; I believe with a level off for a few minutes at 6;000 feet. While working on the QRH; dispatch was messaged to be kept in the loop. The message informed dispatch of pressurization and requested numbers to ORD at 10;000 feet. While climbing from 5-8000 feet it was clear that the manual knob was not functioning correctly. Leaving the knob in the white arc between 11-1 o'clock; we saw cabin descents as high as 3000 FPM; and climbs as high as 2000 FPM. During the climb dispatch informed us we could not get into [destination] because there was a radar outage and he suggested returning. We concurred because the manual controller clearly was not working and we did not feel comfortable flying on to [destination] with a malfunctioning pressurization system. The Checklist here seemed a bit problematic. It suggested pressing the dump button if the manual controller is unsuccessful. We thought the manual controller was successful because the pressurization was at around 4 PSI; so it seemed like dumping would not be the correct course of action. However; it was a little confusing.We took our time flying a wide pattern as we slowly descended down to 3000 feet AGL before turning an extended base. I believe when we joined final we were on a 19 mile final. We took our time returning which I think worked really well with this situation. When we landed; the cabin pressure was 100 feet; while field pressure altitude was probably 900 feet. The outflow valves did not open when we landed. When we turned off PACKS at the gate; the pressure equalized. I have no clue what was broken. I'm guessing it was the electro-pneumatic outflow valve; but something was messed up with the manual outflow valve as well. Additional things I remember was when I realized the pressure error was occurring; I requested autopilot to ease workload. This was around 1200 feet AGL.The aircraft could use better maintenance. Another threat is that the checklist procedure was hard to find; was not that clear; and is not something I've ever thought much about or practiced. I think the checklist procedure is designed for an issue occurring at high altitude; not on climb out. I will say it was an error on my part to not notice the pressurization was 0.0 PSI on the roll. I should have identified that; especially when something felt weird on the roll; and then we could have potentially aborted on the runway instead of taking off. The CA said he has tubes in his ears; so he doesn't notice pressurization; but I noticed something and just couldn't tell. Since I was pilot flying; I don't spend as much time looking at the EICAS as when I am PM (Pilot Monitoring).
EMB145 First Officer experiences a pressurization failure during and after takeoff. After leveling off at low altitude for troubleshooting and attempts at manual control; with little success; the crew elects to return to the departure airport.