Back rivet aft mid longerons to aft side skins. Put 807 balkhead in place and rivet to outboard seat ribs. Rivet baggage rib angles to baggage ribs, install nutplates and rivet to 807 balkhead. Installed nutplates to mid longerons. Clecoed side skins to fuselage. Assemble stab attach bars, 811 and 812 balkheads and tail spring mount to aft bottom skin. Installed lower longerons in place and clecoed assembly to fuselage.