Karl Campbell suggested that info on the Ark Picnic corrision seminar be addressed more fully on the net. I wish I could accomodate by telling more about what John Wright told us, but it was a lot of questions and answers and show and tell regarding samples of corroded parts that John brought with him. The one important point that I took away with me was that much of the spar corrosion on Coupes originates because the spars were not made properly in the first place. Several of the spar suppliers apparently provided spar parts with internal flaws and impurities which subsequently set up a galvanic action which slowly eats away the metal from the inside out--it doesn't necessarily begin on the outside of the spar part. By the time corrision becomes visible it may have already destroyed the part. In addition, there was no tracking of which supplier provided which part or which plane each supplier's part went into. Thus, one wing could have a problem and the other be perfectly fine. This is true of Alon's too. Many of the older Erco parts made there way through other manufactures, including Forney and Alon. That is why the swiss cheese AD is on all coupes. John Wright suggested that inspection of the spars through the swiss cheese holes had to be done with deliberant attention to detail, and that if any area of corrosion was suspected, that some additional attention was called for--such as removing the gas tank, cutting additional holes for better inspection, etc. He also indicated that it was hard to see every where in the wings with just mirrors and a flashlight. It sounds like every coupe owner (or their A&P) should have one of Syd's inspection devices. (Can we still buy that through you Syd? I think it was Syd that invented such a device). John Wright made a point of telling us that the parts he brought for show and tell came off of FLYING airplanes that were in for annuals. In fact, Alvin, one of the attendees at the Ark Picnic, did not have his beautifully painted Coupe at the fly-in because he discovered major corrision in his wings this year. If and when he can find some good wings he will now have to repaint them to match the rest of his fancy paint job, which was only about a year old. That suggest that before investing a chunk of money in new interior, paint or instruments, it would probably be a good idea to have a "John Wright Type" corrosion inspection done--even if that means taking off the wings, etc.
Anyone else at the seminar should put their 2 cents worth in too. Ken Doyle Springfield, Mo Alon N5477E
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