Shawn and I spent hours riveting the skins to the understructure. Encountered some tight areas near the center main bulkhead. Initially when I installed the fwd floor pans and clecoed them in place the fwd lower side skin buckled in. This occurred because the lower fuselage side channel rotated inward in order to secure the floor pan. I decided to drill new holes in the outboard floor pan where it rests upon the the upper flange of the lower side channel. This relieved the stress on the side skin.
