After her return in early December 1965, "Edisto" spent the entire winter in the Bethlehem Steel Shipyard, where she underwent major repairs and alterations. Part of the alterations consisted of installations of a new flight deck with a telescopic hangar to house two helicopters which she would carry. The summer of 1966 saw "Edisto" deployed to the Arctic waters off Greenland and Iceland to participate in "Arctic East Summer" (AES) operations, which entailed the annual resupply of American bases in the Arctic and the advancement of polar sciences. As in the previous winter, "Edisto" was ordered on an unusual winter penetration into northern Baffin Bay.