When you're in flight, the lower pressure above the wing tends to
cause the skin to bulge up a bit, except where it's bonded to the
wing. My Cherokee 180 exhibits this behavior. In flight, you can
see the wing skin lifted slightly above the rivet line.

Hmm. I'm gonna have to check that out next flight.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"