Corrosion within the laminate

[Rich]

Hi Rich,

Thank you, so I will remove the T profile and inspect with an endoscope. But from what I understood, the suspected corrosion of this problem is inside the laminate on the metallic part ? Impossible to see it, isn’t it?

Arnaud.

The idea is to see if it's more than on the exposed outer surface. The real problem is if moisture got into the composite itself and is causing de-lamination. The alternative is not terribly egregious, if it's just to make sure. Pull the wings and replace the screws (and clean up any superficial corrosion). This can't be done in one's typical t-hangar, but I've had the wings pulled (the right one several times) for one reason or another. This particular action wasn't as expensive as you might think. Now this is easy for me to say, as I'm in a financial situation where this expense wouldn't be a big deal.

[astaib]

Hi Rich,

Thank you, so I will remove the T profile and inspect with an endoscope. But from what I understood, the suspected corrosion of this problem is inside the laminate on the metallic part ? Impossible to see it, isn’t it?

Arnaud.

The idea is to see if it's more than on the exposed outer surface. The real problem is if moisture got into the composite itself and is causing de-lamination. The alternative is not terribly egregious, if it's just to make sure. Pull the wings and replace the screws (and clean up any superficial corrosion). This can't be done in one's typical t-hangar, but I've had the wings pulled (the right one several times) for one reason or another. This particular action wasn't as expensive as you might think. Now this is easy for me to say, as I'm in a financial situation where this expense wouldn't be a big deal.

OK, thanks.

I will try with endoscope first. And If I observe rust inside, I pull the wings out at my next annual to make the change of the screws. I hope that it won't get worse between now and my annual (february/march).

Arnaud.

[mhoran]

This issue came up while our plane was at SouthTec undergoing a Major Structural Inspection (MSI). As discussed in the thread, this is not an airworthiness item; though I'd imagine if left unchecked it could become one.

Given we have to have the bonding check performed next year I figured it would be worth fixing this corrosion before it got any worse. We have it on both left and right wings, top and bottom. SouthTec estimates the repair to cost about $1200.