During the annual the A&P noticed when we lifted the weight of the engine that the skin wrinkled on the outside just behind the rear bulk-head on the turtle deck where the green house meets the skin. I was always told that it was not a problem but he opened the skin to see the cause and saw how the wood stringer was attached to the frame by sliding into the U-frame member. It does not have any visible attachment that would keep it from moving as the rear fuselage flexed. The skin has a visible wrinkle on all three points on the turtle deck where the wood stringers attach to the frame. Is this a problem? He had never seen this before so I am keeping him at bay while I do some research. Does anybody know how the wood stringers are supposed to be attached to the frame? He is not to sure how to proceed. I don't think it is an issue, but I am not the A&P..

