Abstract: The invention is a close out fitting for installing in a structural element, the structural element having a port extending from a first surface to a second surface thereof, the port countersunk at both ends, and a method of installing the closeout fitting. In detail, the fitting comprises a hollow, tubular sleeve having a flared first end, a flarable second end and internal threads therebetween. The fitting further comprises a plug having a head portion and a shank portion attached to the head portion with the shank portion having external threads.