Royally P.O.'d at an A&P/IA

bluerooster said:
Now for the $10 question. What causes intergranular corrosion, which, if left un-checked, leads to exfoliation?
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That I would say is not intergranular corrosion. Someone at some time in the past must have spilled something extremely corrosive which soaked into the carpet or it could have been rodent urine. The adjacent floor may have been protected either by glue or tape applied to hold the carpet in place.

Are there any other indications of rodent presence such as gnawed upholstery and such?
 
Silvaire said:
That I would say is not intergranular corrosion. Someone at some time in the past must have spilled something extremely corrosive which soaked into the carpet or it could have been rodent urine. The adjacent floor may have been protected either by glue or tape applied to hold the carpet in place.

Are there any other indications of rodent presence such as gnawed upholstery and such?
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It's an old argument that can't be proved, later stage intergranular, and exfoliation, look the same. It doesn't matter, it has to be repaired.
 
GlennAB1 said:
It's an old argument that can't be proved, later stage intergranular, and exfoliation, look the same. It doesn't matter, it has to be repaired.
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there are X-ray machines that can show the difference.
 
Of course, destructive and nondestructive testing can be used, but for what reason? Ok, it can't be proven without extensive testing. Better?
 
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GlennAB1 said:
Of course, destructive and nondestructive testing can be used, but for what reason?
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To determine the repair? how far back do we have to cut this thing? How much of a patch do we need? Oh this is beyond repair?
 
Tom-D said:
To determine the repair? how far back do we have to cut this thing? How much of a patch do we need? Oh this is beyond repair?
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Been there so many times, you keep removing corrosion till you don't find anymore, that's every SRM requirement I've ever seen. Boeing, Douglas, Lockheed.
 
IGC is normally associated with a material defect usually caused by a manufacturing process error. If this were IGC there would be other Piper seat rails affected, there'd probably be an AD. I've never seen anything like that on a PA28 before, had to be some seriously caustic substance in contact for a lengthy time aided by being retained by the carpet under which there is normally nothing to inspect.
 
GlennAB1 said:
Been there so many times, you keep removing corrosion till you don't find anymore, that's every SRM requirement I've ever seen. Boeing, Douglas, Lockheed.
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We did the Xray thing on every EA6B aft wing spar cracking issue for well over 5 years, corrosion isn't much different in this respect, you dye it remove it, dye it again, rinse and repeat until it is gone. then evaluate what you have.
Xray is simply a hell of a lot easier.
 
We x-rayed L1011wing spars for the same. It was like 30 shots per wing. Sometimes an all day break for the 40 or so mechanics not involved with the inspection.
.
 
With x-ray, you don't just go out blasting, you have a procedure to follow, and there aren't procedures covering the x-ray insp of every part of the aircraft. At least not on the aircraft I've worked on. There are very specific areas and procedures.
 
Silvaire said:
That I would say is not intergranular corrosion. Someone at some time in the past must have spilled something extremely corrosive which soaked into the carpet or it could have been rodent urine. The adjacent floor may have been protected either by glue or tape applied to hold the carpet in place.

Are there any other indications of rodent presence such as gnawed upholstery and such?
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My guess is along those lines, however, two tracks, on opposite sides of the airplane are the only things affected. The skin they attach to is in good shape. The way it's flaking off in layers, and the appearance that it's started internally, leads me to think Intergranular, in the late stages.

And no sign of rodents, but I did find what appeared to be a 30 year old cigarette butt in the tailcone.
 
bluerooster said:
My guess is along those lines, however, two tracks, on opposite sides of the airplane are the only things affected. The skin they attach to is in good shape. The way it's flaking off in layers, and the appearance that it's started internally, leads me to think Intergranular, in the late stages.

And no sign of rodents, but I did find what appeared to be a 30 year old cigarette butt in the tailcone.
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Could these have been replaced previously with sub-standard replacement parts?
 
~$400 for the tracks, cost of rivets, and several hours of my time, plus a few minutes of the IAs time.
 
Um, less than $1K. Ok, I admit I'm new to this game of aircraft ownership, but this kinda sounds like a non event....
 
brian];1979796 said:
Um, less than $1K. Ok, I admit I'm new to this game of aircraft ownership, but this kinda sounds like a non event....
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ya but....let's not discount the story.....and the tears. :D:yes:
 
Non event because the metal underneath was OK.

Glad it was just the track. I just paid for a full engine overhaul at 100 hours post-purchase, so I know the pain and I'm happy you aren't going through it:)
 
Now for the snowballs. I went out today to finish singling up all the extraneous wiring that had been installed over the years. And found a puddle of water in the pilots floorboard forward part. Now where did all that come from? I found that when we get about a foot of rain, it comes in around the fresh air vents. Apparently the gaskets don't last forever. So I'll be replacing them while I have the interrior out. :sigh: And I need to find some (affordable) insulation that doesn't absorb moisture.
 
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