These are detailed in the plans and you must make them. They provide additional stiffness to the forward floor/spar attachment. Clamped the blank in place and backdrilled through spar using a handmade #30 bushing to protect the actual spar hole. I centered a starter hole in the F699 then removed it and opened it up to AN3. Attached it to the spar then used 2 AN3-3A bolts to fill the holes I drilled with the angle drill through the sides. Depending on the spar hole location, you may have to add a spacer between the floor stiffener and the F699 to get proper edge distance where you attach it to the spar.
