 However , he did not remain Chief of Staff for long . He was appointed Chairman of the Joint Chiefs of Staff effective 1 July 1974 . As Chairman , Brown was responsible for the handling of the Turkish invasion of Cyprus in 1974 , and the Mayaguez incident , the final act of the war in Vietnam in 1975 . He also dealt with the 1976 shootings and Axe Murder Incident in the Korean Demilitarized Zone , and oversaw the Panama Canal Treaty in 1977 . 
