ATR 42
Flight Crew Air Transport Pilot (ATP)
Distraction
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Declared Emergency
Aircraft; Human Factors
November 2014 at approximately XA30 hours local I first became aware through my Assistant Chief Pilot that I might have exceeded the aircrafts 0.35 psi landing limitation after landing during an emergency on a few days prior. On November 2014 at approximately XV20 hours local we declared an emergency with ARTCC and Tower due to an inflight cabin depressurization at the beginning of our descent from 13000 feet MSL. We became aware of the depressurization after we received an EXCESS CAB ALT level 3 CCAS warning on the CAP.  I immediately called for the QRH Following Failures Air EXCESS CAB ALT. My First Officer then read out loud section 2.26A in the QRH. Since it was determined that we did not have a rapid depressurization we then followed the 2nd part of section 2.26A in the QRH which mentions- 'If Z cabin > 10000 ft confirmed'. We were greater than 10000 feet and therefore I had my First Officer (FO) attempt to pressurize the aircraft manually.  I then asked my FO to ask for an altitude of 1000 feet MSL in order to maintain VMC conditions due to low scattered clouds in the area. Also; because we were an emergency aircraft I wanted to get on the ground as soon as possible and determined that a visual approach would work best in order to land as safely and quickly as possible. During the descent; I was able to communicate with our Flight Attendant about what had happened. I also did a quick PA to the passengers notifying them that we were descending to a lower altitude due to a loss of cabin pressure. As soon as we arrived at the gate we noticed that the aircraft was pressurizing rapidly and because of the rapid pressurization I then had my FO press the cabin dump button in order to avoid pressurizing so that we could safely open the doors to the aircraft to disembark the passengers. Shortly after securing the aircraft once the passengers had disembarked I was able to talk to one of our mechanics about what had happened. I completely forgot to mention that we had to dump the cabin pressure at the gate and more importantly I completely forgot about the aircrafts landing limitation of 0.35psi prior to landing. Had I remembered about the limitation possibly being exceeded and the fact that we had to dump the cabin pressure at the gate I would have immediately mentioned those issues. I would like to suggest having more cautions and reminders in the QRH especially with the pressurization system.
We had been cleared down to 3200 feet and in the descent we started running our QRH and declared an emergency. We did the items in the 'excess cabin alt' checklist. While in the descent the Flight Attendant (f/a) tried to contact us. We had taken our o2 masks off and our headsets off because they got in the way. It took us a second to be able to respond to her as we found a way to get our mikes to work. I advised her what was going on and that if she needed to give us information to just say it and we would hear it and that we might not respond due to the work load. I also asked if she was ok and she responded yes. As we reached 3200 feet; the Captain elected to descend to 1000 ft.  Since weather was vmc we asked the controllers for 1000 and they approved it. After we reached 1000 ft we contacted so to inform them of our emergency; we also were broadcasting over frequency to advise them of our position and altitude. We got cleared to switch to Tower. We advised them of our position and they cleared us to land. Before we landed both the captain and I wanted to make sure both of us were ok and feeling fine. We both said we were feeling good. I then concerted to f/a to ask the same question and check on the passengers. She said everyone was fine. We landed without incident. I called and told the f/a not to open the door just yet. I didn't look up the procedure for dumping the pressurization but I just thought that if I pressed the 'dump button' the pressure would equalize. It did equalize and pressure returned to zero. I then called the f/a and said she could open the door.
ATR-42 flight crew reported losing cabin pressure in descent. They were able to control pressurization with manual control but landed with pressure exceeding the limit.