Continued work on the center fuselage. Fitted the aft support ribs for the bagage area. Modified the F-725 ribs for the external steps. Fitted the bottom skin, I noticed that the skin was not lined up properly. It was due to the seatbelt mounting brackets getting in the way of the ribs. I removed material from the brackets earlier in the contruction of F-705, but it seems I need to remove a bit more material.