Fuel line leak testing

[steve wyman]

Here's a thought for you guys working on the finish kit. This week I'm running pressure leak checks on the two fuel lines (feed line and return) that run through the center tunnel. I was out of things to do anyway, while I'm waiting for the finish kit at the end of the week. It occured to me after studying the finish kit plans this weekend, just how much stuff (wire bundles, control cables and linkages, etc.) that are layered in on top of the fuel lines, that if you wound up with a leak in one of your flared fittings, you would have a heck of a time rectifying it under all that clutter! Just a thought- but it has been my experience, that whenever something on an airplane becomes relatively hard to reach, that's the thing that will have a problem! Steve

 

[MartySantic]

Steve:

How did you perform the test?

 

[steve wyman]

Steve:

How did you perform the test?

I called Aircraft Spruce and got the following fittings; one each AN807-4D and AN807-6D ( these are a flare fitting( male) on one end and a hose coupling on the other end). I put a piece of clear plastic hose from Ace hardware on each of these hose fittings and screwed the flare end into the flare fittings at the aft end, where the gas tank hooks up to the lines. On the foreward (firewall) end of the lines, I made a short piece of aluminum flared tube and screwed it on to the male flare exiting the gascolator and for the return line the same setup for the union ( AN832-4D ) that I installed to penetrate the firewall shelf. With some short lengths of various size clear tubing and some nylon reducers (all from Ace ) , I Put a balloon on the foreward end. I blew through each hose at the aft end until the balloon inflated, and then capped the aft tube end. I figured if the balloon stayed inflated for an hour on each line, I didn't have any leaks. Pretty much the same setup you will use to pressure test the gas tank. Steve