Club Homepage Forums Classified Ads Buy & Sell - Everything But Airplanes Some corrosion inside 152 Aerobat wings

My broker, a United Airlines pilot, was laid over in San Fransisco and looked over a 1978 152 Aerobat for sale on my behalf (2500TT, 250SMOH). He found evidence of repair for damage in 1982 (hard landing, needed new landing gear bulkhead) and 1984 (slid off runway into snowbank, needed outboard wing repair). The paint is original and in good shape, though it sat outside for the last year or two and the paint is starting to fade on top of the wings. However, he also looked inside one wing inspection hole and found small amounts of corrosion inside the wings on the skin, structure and fasteners. It is a combination of rust discoloration and also white-like powder (aluminum oxide I think). He thinks it is typical of airplanes this age and should not prevent me from buying.

I don't really agree - corrosion, even a small or surface amount inside wing structure, could be serious (particularly on an aerobatic machine). Is this some thing I should check further with an A&P and confirm it is nothing, or walk away from this airplane?

Steven,

As concerned as you are about fatigue failure, please pardon my surprise that you would even consider an aircraft showing obvious corrosion? But, I would agree with your pilot friend, to a point. I doubt that you can find very many of our airplanes with absolutely no corossion. It just depends on where it is manifesting itself to how detrimental it can be. It would warrant further inspection. However, I believe that your lil inner voice has already told you the answer on this particular aircraft.

Corrosion is not only typical, but treatable. We're not flying commercial jets subject to cycling of pressure, temperature, and such - and corrosion in 150/152's is typical, treatable, and not a big deal.

What your source found sounds like the usual minimal surface corrosion.

This is quite common, virtually the norm. Since Cessna did not prime the interior of the structures, the bare Alclad aluminum is exposed to condensation, salt air, enviromental pollutants, etc. Unless an airplane has spent all its life in the western desserts, you can expect to find this fine dusty white powder in almost every Cessna you look at. It will be especially noticable on the inside of the upper surfaces of the wings, which is due to condensation clinging to the skins.

The best cure is something like CorrosionX or simply to do nothing at all, buyers choice.

Its there, deal with it or pass. If you want a truely corrosion proofed airplane, buy a Cessna with a seaplane package installed at the factory, or buy an older Piper Comanche.

Charles

What Charles said!

I can only add that I know of 1 (one) and only one Cessna 152 that has no corrosion at all inside the wings. The owner and I reskined them both, and applied Zinc Chromate while there were open. It took weeks to setup and accomplish! No, 67306 is not for sale!

I don't know yet how extensive the corrosion really is; just that it has been found in a few small areas. Only an A&P looking through the wing can determine if ittruely is not a problem, or if there is serious damage.

Knowing what you know about the condition of this airplane, would you feel comfrotable flying acrobatic manuevers up to +6 and -3 g's in this particular 1978 Aerobat? If you do, and no more corrosion damage is found, then it is a good find.

What exactly will Corrosion X do for me? Will it stop corrosion that has already started? What would the approximate cost be to apply throughout the airframe?

I may have led you to believe that we reskinned the wings due to corrosion! We didn't! There was damage to the leading edge of both wings. In order to properly rivet the new leading edges, the upper skins had to be removed to access the lines of rivets for bucking. These skins were nearly solid white inside from surface corrosion. Although we could have removed the corrosion and alodined and zinc chromated the old skins, it would have been very labor intensive. We chose new skins. It is important that you know that had we reused the old skins, They would have been just as sound as the new skins. We experimented on a small area to see how much material would be removed during complete removal of all corrosion. The new skins measured with a micrometer were .032" thick. The small area of the experiment on the old skins after aggresive mechanical corrosion removal and alodine treatment measured ..... .032" thick. I have since proven there is no difference in strength between properly treated old aluminum, and new, as long as no measureable amount of material is removed, as above! The old skins were kept and used for various other smaller projects. Knowing where to look for serious corrosion issues is an important part of any inspection, but is not very likely to turn up a deal breaker on any well kept aircraft. From your description (hard to see through a computer monitor) what your prospective purchase has is cosmetic in nature, and doesn't weaken the structure one little bit! It is still +6g -3g certified!

Many people use Corrosion-X and other products and believe it helps. I personally do not use the stuff, as I don't want to be constantly cleaning it up as it weeps through lap joints in the skins. When it finally quits weeping, it's time to retreat, so cleaning up after it becomes a fact of life. It also leaves a sticky residue inside, which accumalates all manner of dirt, debris, and bugs, and I don't see how that solves any corrosion issues, other than hiding it. Each to his own!



You should have a pre-buy (you pay) or annual inspection done (negotiate shared costs, but no repairs) before purchase, using YOUR mechanic of choice, and not the one that signed off the previous annual! Listen to your mechanic. That's what you pay him for!

Corrosion X stops the corrosion, inihibits further corrosion, and seeps into the seams of the skin. You're entirely correct - only an A&P can determine if it is a problem. But as far as felling comfortable doing aerobatics in it?

Yep.

I'm starting to believe the same thing. My plane was Corrosion-X'ed about 6-7 years ago and the stuff is still slowly weeping. The inside of the wings have a wet, oily sheen to them which acts like flypaper for dirt.

At best, I'm a fence-sitter on the efficacy of Corrosion-X: If it works, I'm glad it was done to my plane. However, I won't be renewing it - it looks like there's enough already.

My Corrosion-X stopped ?weeping? after a couple of years. Must have something to do with the fact that here in West Texas when we have summer we really have summer. I am guessing that due to the high temperatures the light ends cook off and the ?weeping? ends. It just takes longer for you guys in cooler climes.

This March I pulled one of the wing skins over the fuel tank bay (a fairly easy job now that I have SS screws) just to check on the corrosion situation. Just a described everything was coated with a gooey mass, but no corrosion (big surprise ? not).

I plan to check every couple of years and when the goop isn?t sticky any longer give it another dose of Corrosion-X. Is Corrosion-X be all to end all? I really don?t know. But after my very unhappy experience with corrosion a few years back I just don?t want to take a chance.