The Lockheed AC-130 Spectre is an armed tactical support version of the C-130 Hercules. The AC-130 initially replaced AC-47 & AC-119 in the supporting role during the war in Vietnam. USAF used the AC-130 for close support, area interdiction & force protection. Close air support roles include supporting ground troops, escorting convoys, & flying urban operations. Air interdiction missions are conducted against planned targets & targets of opportunity, whereas force protection missions include defending air bases & other facilities. The AC-130 Gunship arrived in South Vietnam on 21 September 1967 & began combat operations that same year. After the conflict in Vietnam, the U.S. Air Force designed a new range of these aircrafts basing on the C-130 H version, equipped with far more powerful engines, with four-blade propellers & upgraded versions of the navigation & night vision. The AC-130H called '' Spectre'' were used in all the conflicts involving the U.S. Force of the last decade &, after further upgrades, they are still used in the conflict in Afghanistan.