Page 8-13 trimmed the fwd corner of the bottom flange of the aft outboard seat rib cleco'ed the ribs to the rear spar attach bulkhead. fluted the left center bottom skin to match the seat ribs clecoed the skin to the assembly and final drilled the holes to #40 Deburred and primed all of the parts Began riveting the assembly together using the rivet callouts Installed the brackets for the aileron trim. No need to cut the ribs. they have the corner holes and cut out already fabricated. Cleco'ed the template on and match drill the holes. I chose not to use pop rivets so I dimpled and installed the brackets with flush rivets