As has surfaced several times in building, Zenith's configuration control appears to leav something to be desired. The drawings for the seat modification clearly show replacing the existing stiffner around the cutout in the front seat panel 6B15-4 with one that runs the full front-to back distance of the panel. The accompanying text makes fuzzy reference to stifners along either side of the panel, yet these are already present. The drawing is not helpful in this regard.
The replacement stiffner was added.
For the right seat:
1. Remove existing stiffner and nut plates. 2. Cut new stiffner, full front to back length of panel. 3. Positioned new stiffner on panel. 4. Back drilled existing holes into stiffner. 5. Established new rivet line in line with existing rivets. 6. Center punched new rivets, and drilled pilot holes with #40 bit. 7. Opened new holes with #20 bit for A5 rivets. 8. Deburred, cleaned, and primed with zinc chromate primer. 9. Clecoed to seat panel and riveted with A3, A4 and A5 rivets as appropriate. 10. Replaced in aircraft and clecoed. 11. Riveted in place with A5 rivets. 12. Cleaned area, and clecoed seat bottom 6B18-4 in place. 13. Riveted with A5 rivets.
