A320 technicians reported the Aircraft Maintenance Manual (AMM) did not clearly provide defuel instructions for a fuel pump removal procedure. After removing the pump; fuel began to leak; spilling all over on the ramp.
Synopsis
A320 technicians reported the Aircraft Maintenance Manual (AMM) did not clearly provide defuel instructions for a fuel pump removal procedure. After removing the pump; fuel began to leak; spilling all over on the ramp.
Narrative
Supervisor assigned job to a late part that arrived to aircraft. All three mechanics were unfamiliar with job but were aware of the danger of fuel spilling. Arrived at aircraft; pulled breakers before turning on power; and created logbook write-up shorty after. Turned on power; noticed it had 3000 fuel; and asked older mechanics about defueling but after looking into the AMM (Aircraft Maintenance Manual). There was nothing that had details about transferring fuel beforehand; so continued. Proceeded to use the tool referenced in the manual to unseat the valve and started turning. There was a little fuel dripping from the seal as we turned it counterclockwise but not nearly enough for the manual that showed maximum of one bucket; so we kept turning until it started to have a lot of resistance and then proceeded to open the drain plug because then manual said to after the turning stopped. The drain plug showed no signs of fuel so we kept turning because the manual said only in steps beforehand to check the fuel flowing from the valve only after taking the assembly off. As we were turning the valve the keeper lock fell off from the body and dropped into the bucket and then the valve gave out; dropping the cover into the bucket and with a lot of resistance. We managed to lock the valve back in partially. I then had one of the mechanics go tell the Lead that we needed help and we tried to get the valve back in but it was locked in place. To add to this all three mechanics were reading the manual independently and wasn't following one single person reading off the manual.The reference to change the fuel pump had very vague points and at one point told the Mechanic after taking the fuel pump off to gauge the amount that would possible to work with. The manual should reference fuel transferring beforehand to prevent larger spills along with a maximum amount of fuel total before using a fuel truck to drain the fuel if there is too much to transfer all in one wing. The manual highly highlighted the danger of cutting safety wire in red but had other warning orange.
Second reporter narrative
When we were working on Aircraft X; my coworkers were changing left wing tank inboard boost pump. I was helping them after I had done my jobs on the aircraft. We followed AMM (Aircraft Maintenance Manual) steps to remove; but the boost pump is stuck and hard to remove. While I was reviewing the AMM to find a solution related to this problem; other technicians removed the pump but fuel was coming out from the bank. They tried to put the pump back to the tank to stop the fuel; but that did not work. So I helped them put the bump back; also did not work. Because we could not stop and fuel leak; I went to grab fuel leak kit to clean the fuel. At the same time we notified the supervisors.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.