In November 1956, Haynes was ordered to Washington, D.C., and attended Turkish studies at Foreign Service Institute. He was then transferred to Headquarters Marine Corps and served as Special Projects Officer within Operations Division. Haynes was transferred to Ankara, Turkey, in May 1958 and served as Assistant Naval Attache for Air at the American Embassy under Raymond A. Hare. He was also present in Turkey during the 1960 Revolution and served as the principal contact between the embassy and the Turkish military.