Narrative:

On nov/fri/02, I was working on write-up X in conjunction with write-up Y. The discrepancies in question were marked in red or the components trouble spots. I loosened the upper and lower aft bolts on the edp supply shutoff valve, repositioned the valve and retorqued the bolts right and F MM 29-15-94, maintenance manual 20-50-11-0201 and srm 51-40-04. This provided very little clearance between the aileron cables and the valve X, but insufficient clearance between the shutoff valve and the fuel xfeed valve. I then proceeded to loosen the nuts on the fuel xfeed valve a little at a time, assuming the valve might be able to shift enough to provide clearance at the contacting points. About XA40 pm the valve started to leak fuel. I quickly told the mechanic on the headset to inform the cockpit person that we had a fuel leak and power was cut. I noticed where the fuel was leaking, the o-ring that had become unseated on the xfeed valve. I quickly tightened the nuts on the valve and the leak was temporarily stopped. Although we were able to finish our maintenance checks, this error had created an inspection write-up to replace the o-ring in the xfeed valve. The following 2 shifts had transferred fuel and replaced the xfeed valve and o-ring. A functional test was performed, no leaks were found and the aircraft went on a post hmv test flight that evening. All appeared to function normally.

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Original NASA ASRS Text

Title: A B737-500 TECHNICIAN WHILE WORKING TO GAIN CLRNC FOR AN AILERON CABLE, A FUEL XFEED VALVE WAS DISCONNECTED AND MOVED CUTTING THE SEAL CAUSING A FUEL LEAK.

Narrative: ON NOV/FRI/02, I WAS WORKING ON WRITE-UP X IN CONJUNCTION WITH WRITE-UP Y. THE DISCREPANCIES IN QUESTION WERE MARKED IN RED OR THE COMPONENTS TROUBLE SPOTS. I LOOSENED THE UPPER AND LOWER AFT BOLTS ON THE EDP SUPPLY SHUTOFF VALVE, REPOSITIONED THE VALVE AND RETORQUED THE BOLTS R AND F MM 29-15-94, MAINT MANUAL 20-50-11-0201 AND SRM 51-40-04. THIS PROVIDED VERY LITTLE CLRNC BTWN THE AILERON CABLES AND THE VALVE X, BUT INSUFFICIENT CLRNC BTWN THE SHUTOFF VALVE AND THE FUEL XFEED VALVE. I THEN PROCEEDED TO LOOSEN THE NUTS ON THE FUEL XFEED VALVE A LITTLE AT A TIME, ASSUMING THE VALVE MIGHT BE ABLE TO SHIFT ENOUGH TO PROVIDE CLRNC AT THE CONTACTING POINTS. ABOUT XA40 PM THE VALVE STARTED TO LEAK FUEL. I QUICKLY TOLD THE MECH ON THE HEADSET TO INFORM THE COCKPIT PERSON THAT WE HAD A FUEL LEAK AND PWR WAS CUT. I NOTICED WHERE THE FUEL WAS LEAKING, THE O-RING THAT HAD BECOME UNSEATED ON THE XFEED VALVE. I QUICKLY TIGHTENED THE NUTS ON THE VALVE AND THE LEAK WAS TEMPORARILY STOPPED. ALTHOUGH WE WERE ABLE TO FINISH OUR MAINT CHKS, THIS ERROR HAD CREATED AN INSPECTION WRITE-UP TO REPLACE THE O-RING IN THE XFEED VALVE. THE FOLLOWING 2 SHIFTS HAD TRANSFERRED FUEL AND REPLACED THE XFEED VALVE AND O-RING. A FUNCTIONAL TEST WAS PERFORMED, NO LEAKS WERE FOUND AND THE ACFT WENT ON A POST HMV TEST FLT THAT EVENING. ALL APPEARED TO FUNCTION NORMALLY.

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.