The main ribs were clecoed and riveted to the left spar assembly as follows from outboard to inboard: 1 regular W-1210-R. 1 flaperon hinge match-drilled W-1210-R. 4 regular W-1210-R. 1 flaperon hinge match-drilled W-1210-R. 5 regular W-1210-R. 1 W-1210-L with the W-1210B-L doubler.
The left rear spar assembly was clecoed to the aft flanges of the main ribs, two holes were match-drilled #30 into the W-1210-L, after deburring, the whole left rear spar assembly was riveted to the aft flanges of the main ribs.