Narrative:

Took off in foggy conditions. Had to wait for 2600+ RVR to depart due to lack of takeoff alternates (also fogged in). Broke out at 300 feet. At 2500 feet; received passenger door latch caution message. Followed QRH; aircraft was pressurizing normally at the time; continued climb. At 8500 feet; received passenger door warning message. Followed QRH. Aircraft still wasn't high enough to have pressurized much; although cabin was showing 600 feet of altitude; no rate of climb; and delta P of 3.3 and holding. Captain (pilot monitoring) called flight attendant; advised her of situation and asked her to sit in the cabin away from the door. Flight attendant reported no unusual noises from door. QRH directed landing at nearest suitable airport; so we declared an emergency and returned to ZZZ. I transferred controls to the captain in the descent as visibility in ZZZ had gone down to 1600 RVR; requiring a CAT ii ILS. Landed normally and underweight; returned to gate. Contract maintenance inspected aircraft; found door to be badly out of rig; stated to crew that the aircraft was unsafe to fly. Flight canceled; went back to hotel. Prior to pushback; the flight attendant had reported a problem with the door; and the captain went back and closed it. All indications were good however; and we assumed the door was properly secured. (Issues with closing the door are not unusual - I personally don't believe the door was designed for the kind of wear we have in a normal day) after returning; we later learned from a gate agent that the inbound crew the night before couldn't open the door after arrival. Ground crew helped get it open; however no write-up was made. Again; door issues are not uncommon; and this information was received second-hand and I can't verify it. One other intriguing issue - the contract mechanic who first looked at the door told us it was as out of rig as he'd seen the door and the aircraft was unsafe to fly. According to maintenance control; he agreed to approve the airplane for a maintenance ferry flight; but three separate times; changed his mind. Company later sent up one of our mechanics; who approved a one-time; unpressurized ferry flight. Although the maintenance log listed no corrective action; the door felt much more secure than it had the day of the emergency landing. We ferried the flight the next day with no issues or EICAS messages about the door en route. Suggest more frequent inspections of the door.

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Original NASA ASRS Text

Title: CL65 First Officer reports PAX DOOR LATCH caution message at 2500 feet; which progresses to a DOOR warning message at 8500 feet. Emergency is declared and flight returns to departure airport.

Narrative: Took off in foggy conditions. Had to wait for 2600+ RVR to depart due to lack of takeoff alternates (also fogged in). Broke out at 300 feet. At 2500 feet; received PAX DOOR LATCH caution message. Followed QRH; aircraft was pressurizing normally at the time; continued climb. At 8500 feet; received PAX DOOR warning message. Followed QRH. Aircraft still wasn't high enough to have pressurized much; although cabin was showing 600 feet of altitude; no rate of climb; and delta P of 3.3 and holding. Captain (Pilot Monitoring) called Flight Attendant; advised her of situation and asked her to sit in the cabin away from the door. Flight Attendant reported no unusual noises from door. QRH directed landing at nearest suitable airport; so we declared an emergency and returned to ZZZ. I transferred controls to the Captain in the descent as visibility in ZZZ had gone down to 1600 RVR; requiring a CAT II ILS. Landed normally and underweight; returned to gate. Contract Maintenance inspected aircraft; found door to be badly out of rig; stated to crew that the aircraft was unsafe to fly. Flight canceled; went back to hotel. Prior to pushback; the Flight Attendant had reported a problem with the door; and the Captain went back and closed it. All indications were good however; and we assumed the door was properly secured. (Issues with closing the door are not unusual - I personally don't believe the door was designed for the kind of wear we have in a normal day) After returning; we later learned from a Gate Agent that the inbound Crew the night before couldn't open the door after arrival. Ground Crew helped get it open; however no write-up was made. Again; door issues are not uncommon; and this information was received second-hand and I can't verify it. One other intriguing issue - the Contract Mechanic who first looked at the door told us it was as out of rig as he'd seen the door and the aircraft was unsafe to fly. According to Maintenance Control; he agreed to approve the airplane for a maintenance ferry flight; but three separate times; changed his mind. Company later sent up one of our mechanics; who approved a one-time; unpressurized ferry flight. Although the maintenance log listed no corrective action; the door felt much more secure than it had the day of the emergency landing. We ferried the flight the next day with no issues or EICAS messages about the door en route. Suggest more frequent inspections of the door.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.