Cleco center section to bottom skin. Align skin on center section and clamp into place. Match drill 73 holes in aft center skin into aft bulkhead. Counter sink where required. Prepair all F-1204P Left and Right, F-1204T L&R, and F-12046 L&R parts by cutting apart and deburing, and priming. Rivet all parts to bulkhead assembly including skin stiffeners Completed section 20