Narrative:

Departed bos at XA28 local on scheduled air carrier flight. Upon liftoff from runway 22R aircraft would not pressurize. Asked for vectors out of traffic area to run appropriate checklists to try and solve problem. None of our efforts solved problem, so returned to bos in VFR conditions and landed without incident in VFR conditions. Upon inspection of aircraft, mechanics found lower east and east compartment door in open position, which would cause the aircraft to not pressurize. Captain, who preflted aircraft did not notice or discover door open and is possible could have been opened after preflight by maintenance or was not discovered open during preflight. I, myself, ran the interior checks of the aircraft for the first flight of the day and checked that maintenance had singed off the aircraft airworthy before the first flight of the day. Also, all door annunciator lights seemed to check normal and did not show any doors open at that time or before takeoff. We were advised by maintenance at that time they found a faulty door light switch for that east and east compartment door. So, in my estimation, this door open got by 3 possible checks. Having not preflted the exterior of the aircraft, I could not tell you about the door being open! The captain didn't catch it on his walk-around if it was open at that time, and the door annunciator light would not show it to be open. I think the problem would have surfaced sooner had all people involved been paying closer attention to detail.

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Original NASA ASRS Text

Title: UNABLE TO PRESSURIZE. RETURN LAND.

Narrative: DEPARTED BOS AT XA28 LCL ON SCHEDULED ACR FLT. UPON LIFTOFF FROM RWY 22R ACFT WOULD NOT PRESSURIZE. ASKED FOR VECTORS OUT OF TFC AREA TO RUN APPROPRIATE CHKLISTS TO TRY AND SOLVE PROB. NONE OF OUR EFFORTS SOLVED PROB, SO RETURNED TO BOS IN VFR CONDITIONS AND LANDED WITHOUT INCIDENT IN VFR CONDITIONS. UPON INSPECTION OF ACFT, MECHS FOUND LOWER E AND E COMPARTMENT DOOR IN OPEN POS, WHICH WOULD CAUSE THE ACFT TO NOT PRESSURIZE. CAPT, WHO PREFLTED ACFT DID NOT NOTICE OR DISCOVER DOOR OPEN AND IS POSSIBLE COULD HAVE BEEN OPENED AFTER PREFLT BY MAINT OR WAS NOT DISCOVERED OPEN DURING PREFLT. I, MYSELF, RAN THE INTERIOR CHKS OF THE ACFT FOR THE FIRST FLT OF THE DAY AND CHKED THAT MAINT HAD SINGED OFF THE ACFT AIRWORTHY BEFORE THE FIRST FLT OF THE DAY. ALSO, ALL DOOR ANNUNCIATOR LIGHTS SEEMED TO CHK NORMAL AND DID NOT SHOW ANY DOORS OPEN AT THAT TIME OR BEFORE TKOF. WE WERE ADVISED BY MAINT AT THAT TIME THEY FOUND A FAULTY DOOR LIGHT SWITCH FOR THAT E AND E COMPARTMENT DOOR. SO, IN MY ESTIMATION, THIS DOOR OPEN GOT BY 3 POSSIBLE CHKS. HAVING NOT PREFLTED THE EXTERIOR OF THE ACFT, I COULD NOT TELL YOU ABOUT THE DOOR BEING OPEN! THE CAPT DIDN'T CATCH IT ON HIS WALK-AROUND IF IT WAS OPEN AT THAT TIME, AND THE DOOR ANNUNCIATOR LIGHT WOULD NOT SHOW IT TO BE OPEN. I THINK THE PROB WOULD HAVE SURFACED SOONER HAD ALL PEOPLE INVOLVED BEEN PAYING CLOSER ATTN TO DETAIL.

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.