Narrative:

Departed ZZZ at XA54Z, jan/wed/03, bound for ZZZ1. After takeoff, the aircraft sounded very loud. I asked the flight engineer to try to quiet it down. Soon after, we got a pressurization failure (automatic fail and standby) alert on the flight engineer panel. The flight engineer ran the red emergency checklist for pressurization failure 2 times, because we could not stabilize the pressurization. I asked the flight engineer to open the cockpit door, and that is when we knew one of the aircraft doors was open, not closed. We had no door warning lights illuminated, so we assumed the worst case, the main cargo door. I would not let the flight engineer go back to see. The flight engineer strapped in, and we diverted to ZZZ2, declaring an emergency. Upon arrival at ZZZ2, the ground crew could see our crew entry door was popped while we taxied in. The crew entry door did have a history of problems.

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Original NASA ASRS Text

Title: A B727 ON TKOF CLB AT 9000 FT, DIVERTED DUE TO THEIR INABILITY TO PRESSURIZE CABIN. ON GND, FOUND FORWARD ENTRANCE DOOR NOT CLOSED, BUT NO DOOR WARNING.

Narrative: DEPARTED ZZZ AT XA54Z, JAN/WED/03, BOUND FOR ZZZ1. AFTER TKOF, THE ACFT SOUNDED VERY LOUD. I ASKED THE FE TO TRY TO QUIET IT DOWN. SOON AFTER, WE GOT A PRESSURIZATION FAILURE (AUTO FAIL AND STANDBY) ALERT ON THE FE PANEL. THE FE RAN THE RED EMER CHKLIST FOR PRESSURIZATION FAILURE 2 TIMES, BECAUSE WE COULD NOT STABILIZE THE PRESSURIZATION. I ASKED THE FE TO OPEN THE COCKPIT DOOR, AND THAT IS WHEN WE KNEW ONE OF THE ACFT DOORS WAS OPEN, NOT CLOSED. WE HAD NO DOOR WARNING LIGHTS ILLUMINATED, SO WE ASSUMED THE WORST CASE, THE MAIN CARGO DOOR. I WOULD NOT LET THE FE GO BACK TO SEE. THE FE STRAPPED IN, AND WE DIVERTED TO ZZZ2, DECLARING AN EMER. UPON ARR AT ZZZ2, THE GND CREW COULD SEE OUR CREW ENTRY DOOR WAS POPPED WHILE WE TAXIED IN. THE CREW ENTRY DOOR DID HAVE A HISTORY OF PROBS.

Data retrieved from NASA's ASRS site as of July 2007 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.