Installed the inspection panel on the left side of the tunnel. Drilled out the pop rivets and matchdrilled the 21 #40 holes. Installed the cover and matchdrilled the 4 #10 corne holes in order to have a good reference for the cut. Used a step drill to drill the corner holes. I also used a dremel and the angle drill with a cutting wheel to cut out the hole for the inspection panel cover. Filed to measure and slightly adapted the corner for a good fit. I went slightly over on one side, but in general i think that is ok. Unfortunately the primer on the backing plate is still the green Akzo therefore a thin green line is visible when positioning the inspection panel. I will need to paint with the proper color in order to avoid that. I countersunk all the holes (nutplates rivet holes and all #10 holes. I also countersunk the 21 #40 holes for the flush rivets. Deburred and installed the nutplates using the manual squeezer. Installed the backing plate using the manual squeezer and the pull rivets. I don't understand why the instruction indicate LP 4-3 rivets while the original were LP 4-4 slightly longer. The result is that the shop head is smaller than the other pop rivets. Final result looks good.