Corrosion? Corrosion?!

[bluerooster]

I'll show ya corrosion! The seat tracks from my Cherokee.
Interesting that it was isolated to the left and right outboard tracks. The skin underneath was not harmed. But, being a structural component, I was very concerned as to the condition of the skin they were attached to.

 

[bnt83]

Did you post this last year?

I've seen a 7 year old wing/fuselage aileron sector in a jet that was that bad before. The part was about $8k and 20 hours labor to replace

 

[GlennAB1]

That's what happens when aluminum decides to go back to it ore state. It usually starts as intergranular corrosion but is referred to as exfoliation when it gets like that. Improper heat treat is often sighted.