Section 22 Deburred F-1201C Firewall Bottom Pg. 22-02 Step 1: Dimpled the #40 nutplate rivet holes in the Bottom Firewall for the Return Line Clamp. Step 2: Machine Countersunk the nutplate attach holes in the upper sloped flanges of the Lt & Rt Tunnel Ribs and Fwd Fuselage Skin. Machine Countersunk the top hole in the Cooler Stiffener.
