Abstract: A control surface for an aircraft comprise a first skin, a second skin bonded to the first skin, and a stiffening structure located between the first skin and the second skin. The stiffening structure may be formed by forming a plurality of fiber-mandrel sections, stacking the plurality of fiber-mandrel sections to form a fiber-mandrel assembly, and depositing an outer fiber ply around a perimeter of the fiber-mandrel assembly. The control surface may be formed by forming a part layup over a first mold surface, contacting the part layup with a second mold surface, and curing the part layup. Forming the part layup over a first mold surface may include locating a first fiber ply over the first mold surface, locating a plurality stiffening structure assemblies over the first fiber ply, and locating a second fiber ply over the plurality stiffening structure assemblies.