Fuel leak on top of my wing?

[Heybluez]

Looks like my left wing is leaking fuel... It is on top where you enter the cabin. I dont see anything else.. Top or under. How do I fix this? See pic.

P.S. 4th week of ownership and I've already dealt with a fuel pressure Gage issue, FBO that dinged my flap when moving it and now this! Ugh, hopefully I'll get these out early so the rest of the year is event free.

Thanks all!

[Vance Harral]

Fairly common in that location.  You can see there is an inspection panel below the wing walk material, and the leaks are almost certainly coming from that panel.  I try to avoid stepping directly on the panel when getting in/out of the airplane, and I always cringe when a passenger puts the ball of their foot directly on top of it when boarding or exiting.

 

If you were to whittle off the wing walk material above the seeps, you'll likely (hopefully) find inspection panel screws. If so, the leaks can often be fixed just by removing the screws, applying fresh sealant to the threads, and re-installing.  Simple and cheap fix, and the wing walk can be touched up afterwards.  Even if the leaks are from the panel seams instead of the screws, a top-side panel R&R isn't too bad.  But whatever the case, I wouldn't take it lightly - fuel tank sealant repairs always require care.  I'd trust a good MSC with experience in fuel tank patches to do the work, but not necessarily the local mechanic, especially if they've never done it before.

 

Another option if you're tired of maintenance for now, is to do nothing and just keep an eye on it.  The Mooney service manual specifically says "Slow-to-heavy seeps occurring in open areas, such as wing surfaces exposed to the airstream, are leaks which do not constitute a flight hazard and need not be repaired prior to flight, providing the condition causing the leak cannot result in a leak of greater intensity during flight."  A heavy seep is defined as an area of 3.5 to 4 inches, and the wet areas in your photo are smaller than that.  I understand it's disconcerting to see the wet spots, but it's not an airworthiness issue as shown.

[LANCECASPER]

This article under Panel screws explains how to reseal the screw. Some have mentioned that if you use a countersunk washer with the screw it will be a better seal.

 

http://www.donmaxwell.com/publications/MAPA_TEXT/_overlay/Fuel%20Tank%20Repair_How%20We%20Fix%20Them%202-05.htm

[ALP]

I have the same issue you show and one under the paint just outside of the wing walk. If I fill the tank it will blister up a little and then shrink if fuel is less than full. My paint is one year old so I don't want to mess with it. I only fill the tanks to just under 25 gal unless I'm going on a long trip. That seems to control it and I have more useful load.

[Guest]

Depending on the model year, as well as the screws around the access cover there are 4 additional screws attached to a stiffener under the access cover. They are located inboard and outboard of the access panel, usually hidden under the wing walk material.

Clarence

[Shadrach]

Depending on the model year, as well as the screws around the access cover there are 4 additional screws attached to a stiffener under the access cover. They are located inboard and outboard of the access panel, usually hidden under the wing walk material.

Clarence

Clarence, when did they start with stiffener? I believe my 67 F has one.

[Bob - S50]

Personally, I just wouldn't fill the wing up unless I needed the fuel.  Since you have a J, you have 64 gallon tanks.  Do you really need 7 hours of fuel on board?  We (4 partners) park ours with 30 to 35 gallons.  If we need more we add some before flight.  Since my wife doesn't like to be airborne more than about 3 hours without getting out to stretch, that's only about 30 gallons plus 10 reserve.  Filling to the 50 gallon tabs is more than enough.

 

About the only time I add more is when I fly someplace that has cheap gas.  I'll buy enough to get home with the 30 to 35 I'm supposed to park with.  Let's see (taking off my socks so I can count on my toes) park with 32, 3 gallons to get airborne and climb to 8500', that's 35 gallons.  Subtract from 64 leaves 29 gallons for cruise.  Divide by 6 gives me 4.8ish.  Times 100 equals 480 NM.  I can fill the tanks, fly 480 NM (over 3 hours) and still park the plane with 32 gallons.

 

Even if you end up filling the tanks to do that, they won't stay full (and leak) for long.  And if only one wing leaks, burn from that wing first.

 

Bob

(Not just cheap but lazy too!)

[Guest]

Clarence, when did they start with stiffener? I believe my 67 F has one.

Not sure of the exact model and year, but I discovered it when the leak was not at the perimeter screws.

Clarence