Brief Description: Riveted upper stiffner to front of center spar
1. Clecoed top doubler (6ZU2-1) to center spar front. 2. Back drilled seat bottom mounting holes with right angle drill and #20 bit. 3. Back drilled top rivet holes with #20 bit. 4. Disassembled, cleaned, and primed mating surfaces. 5. Reassembled parts and clecoed. 6. Bucked rivets onto face of assembly, per drawing 6ZU2. 7. Riveted top of doubler to existing part with A5 rivets.
