Tonight I have been working on the horizontal stabilizer again. I began with dimpleing both skins, then I riveted the center forward ribs to the skins. These ribs have to be riveted first, since they cant be reached when the forward spar is in place.

Here the rib has been riveted.

After riveting those ribs, I installed the right skin onto the forward spar assy. The forward spar and the forward and aft center rib gets blindriveted together.

Then I riveted the skin to the forward spar and the ribs.

I have to rivet on the left skin as well, before I install the aft spar.