Narrative:

Shortly after takeoff I noticed rumbling noise unfamiliar to me as we started to climb. All three noticed it and we began to speculate what it might be. The suggestion was offered that it might be the external audio panel door may have come open. I discounted this as the noise did not seem to have an associated high frequency vibration that the panel door would give. Next I noticed that my ears were detecting an excessive rate of climb in the aircraft. I checked the pressurization on the second officer's panel and the rate of climb was between 1000 and 1500 FPM. I monitored as the system performed perfectly and went to automatic fail/standby. We leveled the aircraft at 10000' to further investigate he problem. Pressurization was put in manual with no results. The decision was made to return and land. At the gate we found that the east and east compartment was not completely secured. At no time during preflight, taxi, takeoff, landing, or after landing was there any door being unsafe. Twice I visly checked that all warning lights were working properly. Maintenance confirmed that and found that the micro switch at the east and east comp door was not working therefore, not sending a signal to the cockpit that the door was not secure.

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Original NASA ASRS Text

Title: ACR LGT COULD NOT PRESSURIZE AFTER TKOF FROM DEN. POST FLT INSPECTION REVEALED ELECTRICAL ACCESS DOOR NOT FULLY CLOSED AND THE MICRO WARNING SWITCH NOT FUNCTIONING.

Narrative: SHORTLY AFTER TKOF I NOTICED RUMBLING NOISE UNFAMILIAR TO ME AS WE STARTED TO CLB. ALL THREE NOTICED IT AND WE BEGAN TO SPECULATE WHAT IT MIGHT BE. THE SUGGESTION WAS OFFERED THAT IT MIGHT BE THE EXTERNAL AUDIO PANEL DOOR MAY HAVE COME OPEN. I DISCOUNTED THIS AS THE NOISE DID NOT SEEM TO HAVE AN ASSOCIATED HIGH FREQ VIBRATION THAT THE PANEL DOOR WOULD GIVE. NEXT I NOTICED THAT MY EARS WERE DETECTING AN EXCESSIVE RATE OF CLB IN THE ACFT. I CHKED THE PRESSURIZATION ON THE S/O'S PANEL AND THE RATE OF CLB WAS BTWN 1000 AND 1500 FPM. I MONITORED AS THE SYS PERFORMED PERFECTLY AND WENT TO AUTO FAIL/STANDBY. WE LEVELED THE ACFT AT 10000' TO FURTHER INVESTIGATE HE PROB. PRESSURIZATION WAS PUT IN MANUAL WITH NO RESULTS. THE DECISION WAS MADE TO RETURN AND LAND. AT THE GATE WE FOUND THAT THE E AND E COMPARTMENT WAS NOT COMPLETELY SECURED. AT NO TIME DURING PREFLT, TAXI, TKOF, LNDG, OR AFTER LNDG WAS THERE ANY DOOR BEING UNSAFE. TWICE I VISLY CHKED THAT ALL WARNING LIGHTS WERE WORKING PROPERLY. MAINT CONFIRMED THAT AND FOUND THAT THE MICRO SWITCH AT THE E AND E COMP DOOR WAS NOT WORKING THEREFORE, NOT SENDING A SIGNAL TO THE COCKPIT THAT THE DOOR WAS NOT SECURE.

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.