I finally get to install the port and starboard arch supports today. There are existing rivet holes in the top structural longerons that don't match the inner structure or the arch support plate. I'm assuming some revision was made and and I have an old rev. Not to worry though, I just need to align the support plate angle with the arch flanges, clamp it in place and drill new rivet holes.
I matched drill the holes in the arch support and then enlarged them to 5/32" for structural support. I then riveted the assembly on both sides of the aircraft.
