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Over this winter the paint on the upper surfaces of almost the entire plane has developed a "rash". Little (1/4 mm?) blisters scattered across the surface. Spaced pretty uniformly around 10 mm apart. Some surfaces have escaped it but across the wings it's really apparent. Ailerons, cowling, horizontal stabilizer. The fuselage has very little of this effect, same with the flaps. And I see no evidence on the lower surfaces of things.

Another DA40 on the field apparently has the same affliction. Both planes are > 10 years old. My plane was hangared for most of its life, but has been tied down outside for the last 3 winters. I can detect no significant change in flying characteristics. No doubt a paint job in my future.

I just got my plane this year and this has been the first year that it has been outside, with covers and so far I haven't seen anything yet. We have had temps as low a minus 20C. I went flying yesterday and I saw nothing when doing the preflight but will keep my eyes open. Our planes are about the same age.

Rich: I would be interested in seeing detail pictures if you can post some.

There was a similar thread before
http://www.diamondaviators.net/forum/bl ... t3340.html?
Might want to call your insurance

Puncture a blister and see if there's water in it.

Jeff wrote:Rich: I would be interested in seeing detail pictures if you can post some.

Having a hard time getting pictures, but will post when I do.

Moonshine wrote:There was a similar thread before
http://www.diamondaviators.net/forum/bl ... t3340.html?
Might want to call your insurance

The appearance and overall symptoms of my plane are consistent with Lance's post. One very interesting factor: Years ago (2004, I believe), I had a bird strike against the leading edge of the left wing that required about 2 ft. spanwise and perhaps 10 inches chordwise to be patched, feathered in and, of course, the area repainted. This area is totally unaffected by the pox.

There is a large maintenance shop on the field, generally upwind of my plane (and the other one on the field with this problem). They repair/refurbish things like Fed Ex and UPS jets. Boeing does final assembly and lots of test flying here, as they assemble 747's, 777's, and 787's at their plant on the airport. Of course this means a fair amount of test and demo flying. All the panes here keep acquiring a light patina of a sooty substance. Not entirely obvious unless you wipe it a bit with a wet cloth (or hand or whatever).

Investigation continues...

Rich: If they are doing any corrosion work (stripping, treatment, repainting) outside, I wonder if you plane is getting dusted with solvent overspray...

Steve wrote:Rich: If they are doing any corrosion work (stripping, treatment, repainting) outside, I wonder if you plane is getting dusted with solvent overspray...

Could be. It's pretty far away, but it does get windy and rainy such that any effluent could be carried across. What's interesting is the areas that seem unaffected. For example, raindrops/soot is routinely apparent right in and (especially) under the leading edges of the wings and horizontal stabilizer, there is no blistering in these areas.

Rich,

I have unscientifically decided that this is a problem with the aircraft and not environmental. I didn't repaint my plane yet and it happened again. I am guessing that it has to do with moisture and cold. The blisters are between the primer and paint. When I decided to repaint i will have it sanded down to the primer.

Lance