Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP)
Confusion; Distraction; Troubleshooting
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Flight Crew Returned To Departure Airport; Flight Crew Took Evasive Action
Human Factors; Procedure; Environment - Non Weather Related
We took off out after a very normal and uneventful start-up and taxi out. At all times all door indications showed green and closed. As we climbed through around 4;000 feet MSL the First Officer and I noticed the aircraft not pressurizing normally. The cabin rate was climbing at the same rate as the aircraft. No delta Pressure. We were assigned 10;000 feet; but leveled off at 6;000 feet. We ran the QRH and determined the aircraft was not pressurizing at all since the cabin altitude was stable at 6;000 feet. To test it we attempted a climb at 500 FPM to 8;000 feet. Our assumptions were confirmed when the cabin alt climbed at 500 FPM also. We descended back to 6;000 feet MSL. At that point we returned to the departure and taxied into the gate without any other abnormalities.We had no abnormal indications in the cockpit at any time other than the unusual cabin altitude. Once reaching the gate and deplaning the aircraft we found the cargo door not closed flush; but the handle was in the closed and locked position. We had field Maintenance check all seals; edges and tracks for the cargo door. He then ran a pressure test to ensure that was the problem and it was confirmed. Better training of ground personnel (the bag handler that was responsible was very new) and better vigilance of ground personnel when checking all doors closed before pushback.
A CRJ-700 returned to the airport after takeoff because the aircraft was not pressurizing and found that a relatively new employee had not properly closed the cargo door; but no door warning was activated.