Narrative:

We experienced an issue with the main cabin door not properly sealing after takeoff. Just after rotation we received numerous calls from the cabin. We were not able to answer the phone until passing through acceleration [altitude] at which time I noticed we were not pressurizing correctly. When the phone was answered we were told by the flight attendant that the 1L (main cabin door) had not sealed properly and was very noisy and allowing water into the aircraft. After a short conversation we noted that the door handle did appear to be in the fully closed and locked position and the doors page did show the door as closed. The flight attendant did state that the seal was completely deflated and from where he was seated he could see through the door all the way around the seal. By this time we were on our way to our first fix and getting ready to pass through the weather. We asked ATC to turn us back to the airport for a pressurization issue and to keep us away from the weather. We turned onto a right downwind. We kept the airspeed low around (180 KIAS) incase there was any further issue with the door. From here the captain and I had a short discussion on what to do. With the weather closing in and there seeming to be some unknown issue with the main cabin we as the crew elected to continue back for an overweight landing. At this time we asked ATC to turn us south to finish setting up for the approach and talk to the company. The captain loaded the ILS approach and sent a few text messages to dispatch to let them know of our issue and intentions. From this point in time we did attempt to raise maintenance on the company frequency; however; received no response. We were then turned back and were vectored in on a tight base for the ILS (due to weather). An emergency was also declared at this time due to the overweight landing and unknown status of the main cabin door. We still had not received the landing data and decided to use the data cards. The landing was smooth with a soft touchdown at approximately 50-100 FPM sink rate. The landing weight was 63;500 pounds. The only thing not accomplished per policy was a passenger briefing.

Related reports:

Google
 

Original NASA ASRS Text

Title: Q400 flight crew reports a main cabin door seal failure resulting in no pressurization and a call from the forward Flight Attendant reporting the air leak. Flight returns to the departure airport for an overweight landing.

Narrative: We experienced an issue with the main cabin door not properly sealing after takeoff. Just after rotation we received numerous calls from the cabin. We were not able to answer the phone until passing through acceleration [altitude] at which time I noticed we were not pressurizing correctly. When the phone was answered we were told by the flight attendant that the 1L (main cabin door) had not sealed properly and was very noisy and allowing water into the aircraft. After a short conversation we noted that the door handle did appear to be in the fully closed and locked position and the doors page did show the door as closed. The flight attendant did state that the seal was completely deflated and from where he was seated he could see through the door all the way around the seal. By this time we were on our way to our first fix and getting ready to pass through the weather. We asked ATC to turn us back to the airport for a pressurization issue and to keep us away from the weather. We turned onto a right downwind. We kept the airspeed low around (180 KIAS) incase there was any further issue with the door. From here the Captain and I had a short discussion on what to do. With the weather closing in and there seeming to be some unknown issue with the main cabin we as the crew elected to continue back for an overweight landing. At this time we asked ATC to turn us south to finish setting up for the approach and talk to the company. The Captain loaded the ILS approach and sent a few text messages to Dispatch to let them know of our issue and intentions. From this point in time we did attempt to raise Maintenance on the company frequency; however; received no response. We were then turned back and were vectored in on a tight base for the ILS (due to weather). An emergency was also declared at this time due to the overweight landing and unknown status of the main cabin door. We still had not received the landing data and decided to use the data cards. The landing was smooth with a soft touchdown at approximately 50-100 FPM sink rate. The landing weight was 63;500 LBS. The only thing not accomplished per policy was a passenger briefing.

Data retrieved from NASA's ASRS site as of July 2013 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.