Countersunk the nutplate attach holes in the sloped upper flange of the left and right tunnel ribs. Removed protective vinyl and deburred the forward fuselage skin. Countersunk nutplate attach holes in the forward fuselage skin. Removed protective vinyl, deburred, and countersunk nutplate attach and upper most hole in the cooler stiffener. Riveted nutplates to the to the left and right tunnel ribs, and firewall bottom, as directed.
Left and Right Tunnel Ribbs with Nutplated Riveted in Place