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An issue with the center wing spar rib stations presented when fitting the rear ribs. The spar rivet holes are pre-drilled and the flange on the rear rib is not. I noticed that the top and bottom spar web rivet positions were very close to the ends of the rear rib flange, violating the 3 diameter minimum 2 diameter rule for rivets. I spoke with Roger at the factory. and the top and bottom rivets are useless. As a solution, another rivet hole is added at the top and bottom of the rib station thru the nose rib, center wing spar web and the rear rib flange. I also clipped the rear rib flange at the top and bottom to eliminate the offending rivet hole from the rear rib. When complete there are seven A5 rivet positions at the rib station instead of five. Seven rivets hold the nose rib flange to the spar web and five of the rivets hold the rear web flange to the spar web. I have a TD and the nose ribs containing the gear slides already had the extra rivet positions pre-drilled, therefore I only needed to clip the offending rivet positions from the rear ribs. Pictures below show the problem and the solution.