Narrative:

On the morning of mar/tue/02, my aircraft needed a 35 degree valve changed out on the air conditioning system. During the process, I opened both left and right air conditioning bay doors. Before I had finished my project, a team of mechanics showed up to tow my aircraft to the assigned gate. I don't recall closing the air conditioning bay doors, because I had to gather up my tools and rush to the line. The air conditioning system still had ice in the air cycle machine and it was still inoperative. When I arrived at the aircraft, both doors looked like they were up and secured. I reopened the right bay door, put some heat on the system for about 10 mins. After operations checking the system, I closed the bay door and loaded up my tools and drove back to the office to sign the logbook. The pre-departure check was assigned to me. Therefore, I grabbed the logbook and took it to the aircraft. I did an exterior walk of the aircraft, checked oil caps and gave the log back to pilots. The aircraft pushed back for flight 15 mins later, after giving the pilots the logbook. Even though someone else closed the door, I failed to detect that it was not secured all the way. The aircraft left on its flight, and at 12000 ft and flying at 280 KTS, the pilots heard a thump and then noise, probably air rushing past the damaged bay door. The pilots returned to ZZZ and discovered damage to the l-hand air conditioning bay door. I believe some of the leading edge latches were improperly secured. My fault.

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Original NASA ASRS Text

Title: A B737-200 WAS DISPATCHED IN NON COMPLIANCE WITH THE L AIR CONDITIONING BAY DOOR NOT SECURED. ACFT RETURNED TO GATE WITH DAMAGED DOOR.

Narrative: ON THE MORNING OF MAR/TUE/02, MY ACFT NEEDED A 35 DEG VALVE CHANGED OUT ON THE AIR CONDITIONING SYS. DURING THE PROCESS, I OPENED BOTH L AND R AIR CONDITIONING BAY DOORS. BEFORE I HAD FINISHED MY PROJECT, A TEAM OF MECHS SHOWED UP TO TOW MY ACFT TO THE ASSIGNED GATE. I DON'T RECALL CLOSING THE AIR CONDITIONING BAY DOORS, BECAUSE I HAD TO GATHER UP MY TOOLS AND RUSH TO THE LINE. THE AIR CONDITIONING SYS STILL HAD ICE IN THE AIR CYCLE MACHINE AND IT WAS STILL INOP. WHEN I ARRIVED AT THE ACFT, BOTH DOORS LOOKED LIKE THEY WERE UP AND SECURED. I REOPENED THE R BAY DOOR, PUT SOME HEAT ON THE SYS FOR ABOUT 10 MINS. AFTER OPS CHKING THE SYS, I CLOSED THE BAY DOOR AND LOADED UP MY TOOLS AND DROVE BACK TO THE OFFICE TO SIGN THE LOGBOOK. THE PRE-DEP CHK WAS ASSIGNED TO ME. THEREFORE, I GRABBED THE LOGBOOK AND TOOK IT TO THE ACFT. I DID AN EXTERIOR WALK OF THE ACFT, CHKED OIL CAPS AND GAVE THE LOG BACK TO PLTS. THE ACFT PUSHED BACK FOR FLT 15 MINS LATER, AFTER GIVING THE PLTS THE LOGBOOK. EVEN THOUGH SOMEONE ELSE CLOSED THE DOOR, I FAILED TO DETECT THAT IT WAS NOT SECURED ALL THE WAY. THE ACFT LEFT ON ITS FLT, AND AT 12000 FT AND FLYING AT 280 KTS, THE PLTS HEARD A THUMP AND THEN NOISE, PROBABLY AIR RUSHING PAST THE DAMAGED BAY DOOR. THE PLTS RETURNED TO ZZZ AND DISCOVERED DAMAGE TO THE L-HAND AIR CONDITIONING BAY DOOR. I BELIEVE SOME OF THE LEADING EDGE LATCHES WERE IMPROPERLY SECURED. MY FAULT.

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.