1. Clamp upper center wing guide to the upper spar box plate. Ends of block are roundedmay need to be beveled to fit around welds. Flat side should be against the spar caps. The thick end should be to the rear for the upper guide. Center of guide block should be in center of holes on spar plate.
2. Transfer drill 11/64” hole through plate into guide block.
3. Repeat for lower center guide. The thick part of the lower guide block should be forward.
4. Remove guide blocks. They will be installed after bottom skin is installed.
