Narrative:

Upon departure we (the flight crew consisting of 'pilot flying'; 'pilot not flying' and myself as observer relief pilot) realized the cabin would not pressurize. We were also informed by the cabin crew that there was substantial noise in the passenger compartment coming from the L1 door. We stopped the climb at 9000 ft MSL; declared emergency with request to return to aerodrome of departure; and held over while we performed the company emergency; non normal/normal procedures. Upon completion of the above mentioned procedures we set up for the ILS and completed and approach to an overweight landing without incident. Upon landing and checking brake cooling charts for turnaround time we arrived at remote parking position and made certain all after landing flows and checklists where in fact completed and performed correctly. R1 door was utilized to exit the aircraft and after further investigation it was determined that the aft top roller pin of the L1 door did not go into its groove; thereby leaving door not up against the frame to seal properly. We had no indication of this on the flight deck since the micro switch for the door annunciation is on the forward top roller pin which in fact was in its groove. As a new procedure our company has instituted a new policy of checking the door against its frame upon closing of the door and also as prior protocol; checking to see exterior handle is stowed properly (which was not the issue in this case) prior to closing the door. Upon refueling; waiting on the brake cooling chart times and an overweight landing inspection by our onboard maintenance technician we were given the 'green light' to proceed with the flight. The second attempt of the flight was completed without further incident.

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Original NASA ASRS Text

Title: The top locking roller of a B737-800s L1 door did not seat when the door was closed; leaving a gap which prevented the aircraft from pressurizing. Door indications were normal. The crew declared an emergency and returned to land.

Narrative: Upon departure we (the flight crew consisting of 'pilot flying'; 'pilot not flying' and myself as observer relief pilot) realized the cabin would not pressurize. We were also informed by the cabin crew that there was substantial noise in the passenger compartment coming from the L1 door. We stopped the climb at 9000 FT MSL; declared emergency with request to return to Aerodrome of departure; and held over while we performed the company emergency; non normal/normal procedures. Upon completion of the above mentioned procedures we set up for the ILS and completed and approach to an overweight landing without incident. Upon landing and checking brake cooling charts for turnaround time we arrived at remote parking position and made certain all after landing flows and checklists where in fact completed and performed correctly. R1 door was utilized to exit the aircraft and after further investigation it was determined that the aft top roller pin of the L1 door did not go into its groove; thereby leaving door not up against the frame to seal properly. We had no indication of this on the flight deck since the micro switch for the door annunciation is on the forward top roller pin which in fact was in its groove. As a new procedure our company has instituted a new policy of checking the door against its frame upon closing of the door and also as prior protocol; checking to see exterior handle is stowed properly (which was not the issue in this case) prior to closing the door. Upon refueling; waiting on the brake cooling chart times and an overweight landing inspection by our onboard maintenance technician we were given the 'green light' to proceed with the flight. The second attempt of the flight was completed without further incident.

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.