Help with left fuel line & control wire bushing

[KewFlyer]

Group:
Once more, I go to the welll for advice.
This past week end I noticed a noice coming from the upper left side of the windshield, where it meets the headlinner, when the ailerons are in use. After further investigation, I found that when the ailerons are used, the control wire rubs on the left aluminum fuel line when both come down from behind the headlinner. After opening the headlinner, it appears that the fuel line has twisted or moved and now both are sharing the same location, side by side. It is not that bad on the horizontal travel right on top of the door frame, since the fuel valve moves the fuel line away from the control wire, but is really bad when they turn down at the control wire bushing and run down the door post and into underneth the instrument panel.
Any suggestion on how to separate them? Specially at the top bushing and down from there. I would hate to force bend the aluminum fuel line away and do some damage some place else, or kink it or...
Advice is welcome !!
Thanks in advance
Ralph
Grouded for now, until the situation is repaired

[VictorBravo]

Re: Help with left fuel line & control wire bushing

Make a VERY slight bend in the fuel line with your hands (no tools), at least four or five inches AWAY from where it rubs on the control cable. A small bend far away from the rubbing point will give you the same clearance as a severe bend very close to the rubbing point. From several inches away from the rubbing point, you may only have to bend the aluminum fuel line half a degree to solve the problem.

Once you have bent the fuel line and solved the rubbing, make a CLOSE inspection of the abrasion to the fuel line. If it just made a shiny spot that's no problem... but if the cable wore a groove into the aluminum tube then it must be replaced.

Once you have determined that there is no real damage to the fuel line, wrap it with a layer or two of plain white masking tape in that area. This way you will be able to see a dark mark on the masking tape if the cable starts to rub it again. Until you are 100% certain that the problem is permanently solved, look at this fuel line every few flights to make sure you are not getting any further damage.

[t-crafter]

Re: Help with left fuel line & control wire bushing

There should be an adel clamp near the top of the door post, holding the fuel line away from the control cable. Something must have moved to allowed the fuel line to interfere with the cable. Carlton

[KewFlyer]

Re: Help with left fuel line & control wire bushing

Bill & T-crafter:
Thank you for the advice in correcting this situation. It appears, after a second inspection, that the fuel line is running parallel and very close to the left aileron wire between the valve and the bushing that turns both down the door post, and they continue to do so on the way down to.
I'll back at the hangar tomorrow and will try Bill's approach of bending away so the line moves enough where needed, as well as maybe installing a clip to support the fuel line as it turns down next to the bushing, as well as along the path downwards...maybe one or two clips more.
Also, after inspecting the fuel line, there are no markings that could have been made by the rubbing of the wire..... = good news.
Thanks again
Regards,
Ralph

[KewFlyer]

Re: Help with left fuel line & control wire bushing

Well... we tried but no lollipop this time.
The fuel line has very little to no slack. We were able to move the fuel line from the fuel valve to the bushing, by doing a small bend about 4" from the fuel valve. From the bushing down, there's no slack availalbe to bend or re-route the fuel line. The next step would be to do a small bend before the bushing and a second one after the bushing.. two small ones may do it. The first one would move the line up and forward (? dont ask me wye but the lien moves that way) the second bend would move the ilen away from the aileron wire. Any ideas?

until next week and thanks for the inputs.
Ralph

[N96337]

Re: Help with left fuel line & control wire bushing

Ralph,
Maybe these drawings from the Gilberti STC will help you with the routing... just remember to keep everything flowing downhill all the time or they tend to not want to start flowing as nicely.
John

[KewFlyer]

Re: Help with left fuel line & control wire bushing

Thanks John.
Absolutly. Thats one of the issues we discussed before bending the line. As pointed out by Victor Bravo, bends away from a problem area will generate a larger sweep where needed. With that in mind, a small bend at the exit of the fuel valve would move the fuel line upwards and away of the bushing = vertical move. This small bend would stioll provide for gravity feed into the nose tank from the left wing tank. Once that's accomplished, then the problem of moving the fuel line away from the aileron control cable = downwards, becomes the issue since the is no slack in the fuel lline to make a second bend at the bushing. I am thinking on just doing a small enough bend at the exit of the fuel valve to insert a small srew+clamp to permanently route the fuel line away from the bushing = just 1/4" clearance at the bushing would do it. And then a second screw+clamp foward of the bushing or there abouts to move the fuel line away from the control cable on the downwards travel. If too much bend is done, I would have to do a dive to transfer fuel from the left tank into the nose tank

Any advice is welcome. Saturday will be the scheduled work day.
Thanks
Ralph

[Pearson]

Re: Help with left fuel line & control wire bushing

Ralph,

If you go to this website, http://www.aircraftspruce.com/catalo...spiralwrap.php , you will see the type of stuff that my mechanic wrapped around both of my wing tank fuel lines when we relocated the valves. You can screw it on without having to remove either end of the fuel line. It is very inexpensive and will keep the cables from rubbing into the fuel line. It is pretty hard plastic.