Machine Countersunk holes for doubler Nutplates in Fwd and Aft Spars. Riveted Doublers and Nutplates to Fwd Spar. Riveted Nutplates for Upper and Lower Horns to Fwd and Aft Spars. Riveted Nutplates to Hinge Brackets. Riveted Counterbalance Brackets to Fwd and Aft Spars.
