Match drill and rivet top joining channels

Having verified the longitudinal alignment of these channels, using the side skins and the top rails and the jig derived from it, it was then necessary to rivet the top joining channels into the aft fuselage. There is a line of rivets running along the outside exterior as well as along the top. With the channels clecoed into the side skins, the top row of holes were found to misalign laterally and to some extent longitudinally by up to 0.7mm. It was decided to upsize these holes to 4.1mm for 4mm rivets. The RHS channel was so modified some months ago, before the rear skins were attached, Now I had to modify the LHS channel with the rear skins now attached. While extremely difficult, particularly for the rivets close to the rear arch rib, I got it done.