Fuselage mandrel insert and method

An apparatus for use in formation of a composite structure about a mandrel. A generally flexible pneumatic tool and a generally rigid insert are inserted end to end in a cavity of the mandrel. A first end of the insert is positioned in the cavity, adjacent the pneumatic tool, and defines an interface therebetween. The retainer is connected to the insert proximate the first end of the insert. The retainer has an end that extends outwardly from the first end of the insert across the interface and over a portion of the end of the pneumatic tool. The uppermost surfaces of the insert, retainer, and pneumatic tool are generally flush with one another and facilitate a smooth surface being formed over such uppermost surfaces as the composite material is wound about the mandrel in the formation of the composite structure.