Rivet top skin to inner ribs. Then, start on flap spar by riveting the 1st piece of angle to the end of the spar, using the 5 inside rivet holes only. Rivet the other two pieces of the flap attach brace together but don't install those yet. Put to end ribs in place and rivet them to the spar. Take that assembly and put it inside the flap skin. Use LP4-3 s to attach the spar to the inner ribs. Rivet the top skin to the spar and end ribs. Turn it over and rivet the bottom skin to the outer ribs. Once you have the outer ribs finished you can install the rst of the flap attach brace. The bottom of that brace gets CS4 pop rivets.
