Skin Use MS20470AD4 or MS20600 self-plugging rivets or equivalent 0.25" edge distance Patch 0.016" Alclad$^{TM}$ 2024-T4 0.75 ˝ rivet  spacing 0.25" radius Cut out damaged area Figure 4-179.  Beaded skin repair on corrugated surfaces.  Repairs to a Pressurized Area The skin of aircraft that are pressurized during flight is highly  stressed. The pressurization cycles apply loads to the skin,  and the repairs to this type of structure requires more rivets  than a repair to a nonpressurized skin.  [Figure 4-182] 1.  Remove the damaged skin section. 2.  Radius all corners to 0.5-inch. 3.  Fabricate a doubler of the same type of material as,  but of one size greater thickness than, the skin. The  size of the doubler depends on the number of rows,  edge distance, and rivets spacing. 4.  Fabricate an insert of the same material and same  thickness as the damaged skin. The skin to insert  clearance is typically 0.015-inch to 0.035-inch. 5.  Drill the holes through the doubler, insertion, and  original skin. 6.  Spread a thin layer of sealant on the doubler and secure  the doubler to the skin with Clecos. 7.  Use the same type of fastener as in the surrounding  area, and install the doubler to the skin and the  insertion to the doubler. Dip all fasteners in the sealant  before installation. 4-101