Mckelvey was the last of the 630 servicemen from Philadelphia to die in the Vietnam Theater of Operations during the Vietnam Era, which the Department of Defense defines as the period from August 1964 through May 1975. The 23-year-old Air Force sergeant was killed when the CH~53 helicopter in which he was riding crashed 35 miles south-west of Nakhon Phanom, Thailand, on May 13, 1975. MeKelvey had left Roxborough High School in 1969 at the age of 17 to enlist. He was assigned to the 56th Security Police Squadron in Vietnam. McKelvey had married a Thai woman and planned to adopt her daughter. In addition to his wife, he was survived by his parents and a sister.