Section 17 is the outboard leading edge of the wing. My little sister, Hannah, was visiting and like any good big brother would do I put her right to work! She was very helpful and worked the clecos like a pro. The ribs were all put in, match drilled, deburred, etc. The ribs were kind of a tight fit in some spots to get them to line up perfectly. Had to break out the rubber mallot a few times.