Thick black sticky residue under my wing.

SixPapaCharlie

SixPapaCharlie

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When I was pre-flighting my plane I noticed I had overfilled my fuel tanks and had some blue dye on my landing gear which is typical when I put too much fuel in however when I was looking down there I noticed significant streaks of black mixed in with the blue. The only way to describe it is it's like tar or rubber cement.

I have bladders in the plane. I pulled some inspection panels and looked around the area where the auxiliary bladder is and it's bone dry and the bladder appears to be in almost new condition. I was nervous that maybe it was starting to rot or break down or something the fuel was dissolving it and taking parts of it out the seam.

Call me look into the auxiliary so far. Just because I've had issues with that tank unrelated in the past..

Any thoughts on what this substance might be. I feel like the fuel is solving something and then it's drying on the bottom of the wing.

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Be curious thing about it and I don't think the photo really shows it is that it's thick gummy. It's not just stains like oil or fuel.
 
Looks like grease. Possibly some thing was over greased, maybe in the wheel struts? Did you recently have maintenance done?
 
I'm not a maintenance expert so I'm sure someone more qualified will chime in, but I have seen this on an old 182 with bladder tanks. Seems like a connection.
 
bflynn said:
Looks like grease. Possibly some thing was over greased, maybe in the wheel struts? Did you recently have maintenance done?
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No recent maintenance and that was my first thought when I saw it is it looks like Greece It's just the texture doesn't add up You can kind of grab it and peel it off to some extent it certainly very sticky but it has the consistency of tar
 
dmspilot said:
I'm not a maintenance expert so I'm sure someone more qualified will chime in, but I have seen this on an old 182 with bladder tanks. Seems like a connection.
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Did the person with the 182 seem like it was really expensive to fix? :)
 
Do you have access to a borescope camera? The part you're looking at may be fine, but a seam around the corner may not be.

I'd locate the fuel vents and just double check you didnt unclog something from there.

If nothing, then I'd clean it up and keep an eye on it. Could be possible you flew through something and are just now seeing it.
 
guest user said:
Do you have access to a borescope camera? The part you're looking at may be fine, but a seam around the corner may not be.

I'd locate the fuel vents and just double check you didnt unclog something from there.

If nothing, then I'd clean it up and keep an eye on it. Could be possible you flew through something and are just now seeing it.
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I do have a borescope. so far most of what I have looked has been bone dry. I did find a birds nest though.
 
It kind of looks like the corrosion x that bleeds out of my plane, but I don't really get sticky globs of it like that. Of course, I also don't dump gallons of avgas through my wings, either :biggrin:
 
Jim K said:
It kind of looks like the corrosion x that bleeds out of my plane, but I don't really get sticky globs of it like that. Of course, I also don't dump gallons of avgas through my wings, either :biggrin:
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HAHA!!!

Yes someone did corrosion X my plane and it does weep out endlessly.
Dumping gallons of avgas is the only way to clean the inside parts
 
That looks like the mess I had when my mechanic used some black RTV that didn't setup before flying. It took hours to get it all off the paint where it had streamlined back
 
The sticky goo is tape adhesive. When they install (or replace) the bladder, it's standard procedure to tape over all of the seams and rivet heads in the bay so they don't poke or abrade the bladder and shorten it's life. When the bladder starts to leak, the fuel dissolves the tape adhesive, mixes with it, and it leaks out of the wing making sticky, gooey stains like you have in your photos.

Sorry to be the bearer of bad news, but I think your initial suspicion is correct.

C.
 
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camorton said:
The sticky goo is tape adhesive. When they install (or replace) the bladder, it's standard to procedure to tape over all of the seems and rivet heads in the bay so they don't poke or abrade the bladder and shorten it's life. When the bladder starts to leak, the fuel dissolves the tape adhesive, mixes with it, and it leaks out of the wing making sticky, gooey stains like you have in your photos.

Sorry to be the bearer of bad news, but I think your initial suspicion is correct.

C.
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Could you phrase your answer in the form of a song, please?
 
camorton said:
The sticky goo is tape adhesive. When they install (or replace) the bladder, it's standard to procedure to tape over all of the seems and rivet heads in the bay so they don't poke or abrade the bladder and shorten it's life. When the bladder starts to leak, the fuel dissolves the tape adhesive, mixes with it, and it leaks out of the wing making sticky, gooey stains like you have in your photos.

Sorry to be the bearer of bad news, but I think your initial suspicion is correct.

C.
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so if I understand correctly, even if his bladders are fine, the overflow has washed away the tape's mastic...likely leaving his bladders unprotected from abrasion.
 
Good comments and input on what the problem(s) may be. Here’s your solution to cleaning it up though:

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could'a flown thru those t-storms on the way home to clean that right up
 
Some aircraft have a sort of “standpipe” to COMPLETELY fill bladders

for leak checking. IIRC there is an AD mandating this for certain bladders.
 
This being almost summertime, and Bryan being in Texas, I was expecting tires sunk into the asphalt.
 
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