Early in 1966, "Ability" embarked upon another assignment with the 6th Fleet. In February, soon after her arrival in the Mediterranean, she participated in the search for an American nuclear device lost when two Air Force planes, a B-52 bomber and a KC-135 cargo plane, collided in midair. Otherwise, the deployment consisted of the usual exercises and port visits. "Ability" returned to Charleston on 13 July 1966 and resumed services to the Mine Defense Laboratory and the Mine Warfare School. That employment lasted until 11 May 1967, when she shaped a course for Montreal, Canada, to make a goodwill visit to the world's fair at that city, Expo '67. After also visiting Quebec, the minesweeper resumed her normal duties at Charleston on 9 June 1967.