Fuel tank leak on CTLS

[Linden1]

Noticed this staining on the wing seal tape and CTLS fuselage near the wing root this morning.  Last flew two weeks ago.  Removed tape and could see by the staining that fuel had come through the narrow horizontal opening mid wing where wing and fuselage meet.  No smell of gas, wet area or any sign of ongoing leak.  Fuel level is where I last recall it at 25 gallons.  I have flown twice since topping off the tank.  

Wondering if this is a tank leak or failing hose?  No sign of any discoloring or composite failure on bottom of wing.  Also not sure whether safe to fly to my mechanic so he can remove wing to inspect.  As always, appreciate any insights from the board.  

 

 

[Doug G.]

I have been through this. It is likely from the access port on the wing root. The first thing I would try is tightening the six nuts on that port (this was advice from Adrian at FDUSA). If that does not work you will need to pull the wing, remove the plate covering the port and reseal it with a thin layer of Hylomar. 

There is one more possibility for the leak and that is the fuel nipple which would also require the removal of the wing and removing the port to get access to back side of the fuel nipple.

[Tom Baker]

One other thing I have seen, especially if the tank was full is a leaking vent line.

If it is not dripping I wouldn't be afraid to fly the airplane somewhere to get it fixed, but I would talk with your mechanic first.

In addition to the Hylomar Doug mentioned there is also a gasket.

[Doug G.]

Thanks Tom. Yes, there is a gasket on the opening. I forgot to mention that the nuts can be tightened through the sight tube opening. (With the right tools. Some of them are hard to get at,)

[Linden1]

Thanks gentleman, reviewed the maintenance manual which helped me understand the fuel line  plumbing.   Contacting my mechanic although helpful to learn from others experience.  

 

 

[Tom Baker]

Roger, maybe you should post the info here, it might be of help to someone when you are not around to take the call.

[Doug G.]

I guess I am a rarity. And, Arian said that the leaking around the bulkhead fuel plate is often fixed by tightened Nguyen the nuts, so evidently he has seen it before. So maybe not that rare.

Roger, are you saying that it is possible to put Hylomar on the fitting without accessing it from inside the tank and have it seal?

[Doug G.]

Thanks for this Roger. I will take a closer look at that clamp and opening next time I have the wing pulled.

[Tom Baker]

I have used a Band-it back like the factory before. It is not my first choice, but the hose stays in place and doesn't leak.

[WmInce]

7 hours ago, Roger Lee said:

I'll post the SW leak fix shortly.

That's appreciated, Roger, thank you.

[Linden1]

CTLS Fuel bulkhead plate with 6 nuts is very clean with no signs of any staining in chamber.  Must be the fuel line where it connects to the nozzle on the bulkhead as Roger suggests.  Tried to view with an endoscope but that area is closed off.  

Will slide out wing next.  Curious if anyone knows a Repairman in the Chicago metro area with Flight Design experience that could do a house call.  My plane was converted to experimental. 

Thanks all, Happy Memorial Day.  

 

[WmInce]

Thank you, Roger!

[Runtoeat]

Hi Roger.  Thanks for the detailed method for sealing the fitting.  There are many types of hylomar shown on the internet.  If you might provide the number and/or name of the hylomar you use, it would be appreciated.  I'm wondering if there is a type that is specifically required for MoGas with ethanol?  I have found that hylomar did not work when used on the paper gasket used for the fuel filler fixture in my wing.  This fixture leaked soon after being installed.  When the leaking fixture was pulled out of the wing, it was obvious that fuel had worked it's way past the paper gasket which had the 'blue" sealant on it.  I believe the mechanic used hylomar but am not certain.  If he did use hylomar, I'm not sure which type he used.

[Runtoeat]

Thanks Roger.

[CT2K]

Sorry if a late contribution. I got similar thin leak at the same area, I noticed it in March, after first flights after winter. Pulling the wing back it appeared to come from the pin that connects the wing to the fuselage. That pin is located between leading edge and wing spar. It seems to have some sorts of gasket and the thin leak came from there. It needed resin work around the pin by a dedicated shop where they said they also poured some liquid sealing inside the tank and flipped the wing around long enough to get the sealing coat all the interior of the tank.

[Doug G.]

That sounds like a tank leak. The pin was just where it showed up.

[CT2K]

@ Doug, many thanks for your thought,, it throws some light. I was thinkg the dark material around the pin (when the wing got pulled back) was some gasket or a black rubber,, now with what you say I better understand. That must be the reason the shop used resin to repare that area on my CT.

[Greg]

Roger

What is used to bind the fuel filler fixture to the composit wing.  A lineman pryied mine out with the fuel hose nozzel.  I tried some fuel tank repair two part epoxies from Ace but the gas is breaking them down to soft and letting the fixture come loose.

Thanks.   Greg 

[Greg]

Thanks Roger.  I totally agree with putting in fuel myself.  I was in Lakefront New Orleans and got lazy.  Never again. 

Two tips for getting home for those with loose fuel fittings.  Take the fitting and fuel cap out and pound a large aluminum foil ball in the hole until it is flat with surface. Amazing how well it works and will get you home.  Or, tape it down.  Duck tape will work for awhile but the fuel breaks it down.  Use the blue paint line tape.  Designed to be solvent resistant and easily available.  Make sure you run tape over and under the leading edge of wing.  Seal it tight or vacuum will form and prevent fuel flow from that tank. 

[Runtoeat]

Greg, I have had my fuel filler resealed on my CTSW.  This is held in with 4 screws. Due to the screws retaining my filler, my mechanic used a new gasket and Proseal to seal the filler.  It appears that you have a CTLS based on your comments about the line man popping it out of the wing.  The CTLS has no retention screws and is just held in by the epoxy.  In this case, I believe that you would want to use the Creme Weiss epoxy since this would seal and retain the filler.  Roger has expertise and experience but isn't in your area.  Someone with good experience and expertise on CTLS would be best for repair.  Thanks for the good info for the temporary fix with foil and blue tape.

[Duane Jefts]

Copper City on this site has repaired some and should know the correct epoxy to use.

[coppercity]

The product I got from Flight Design to repair my filler caps was a two part epoxy called EpoFlex I believe.  Not sure that product is still available but check with Arian at FDUSA, they can likely send you a small batch of the current product to get the job done.