Private First Class Coulam was a member of Company B, 14th Engineer Combat Battalion, U.S. Army. On 14 November 1952, he was a passenger aboard a C-119C, "Flying Boxcar" from the 63rd Troop Carrier Squadron, 403rd Troop Carrier Group enroute from Ashiya Air Base, Japan, to Seoul, Korea, when it crashed into Hill 683 near Cho-ok and about 15 miles east of Haeju Airfield (K-19), killing all 44 servicemen on board.

Coulam was awarded the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.