The Lockheed Martin AC-130 Spectre gunship is a heavily armed ground attack variant of the C-130 Hercules. This military aircraft was developed during the Vietnam War. It made its first flight in 1966. The type was adopted by the US Air Force (USAF) in 1968. It replaced the previous Douglas AC-47 Spooky gunship. A total of 47 of AC-130 gunships, including variants, were converted from C-130 transports. In 2018 the type will be operational for 50 years. This gunship was never exported outside the United States.

   The main role of this unusual aircraft is close air support. It can engage enemy positions, protect ground troops or escort convoys. The aircraft can deliver accurate and continuous fire to a single point on the ground. The AC-130 gunships are flown by special operation squadrons.

   This aircraft is capable of flying faster than helicopters, operate at higher altitudes, has much longer loiter time in the target area, can carry much heavier armament and much more ammunition.

   Weapons are mounted in a way to fire from the port side of the fuselage. During an attack the gunship is flying in a large circle around the targets. So this aircraft can fire at the target for much longer time than helicopters, conventional ground attack aircraft, or multi-role fighters.

   Different variants of this aircraft have different armament. The original AC-130A was armed with four 7.62-mm GAU-2/A miniguns and four 20-mm M61 Vulcan cannons. Upgraded AC-130E and AC-130H aircraft packed even more formidable punch. These were armed with two 20-mm M61 Vulcan cannons, one 40-mm Bofors cannon and one 105-mm M102 howitzer. The current AC-130U is armed with a 25-mm GAU-12 Equalizer cannon, one 40-mm Bofors cannon and one 105-mm M102 howitzer.

   This aircraft has a sophisticated fire control system. However it relies on visual targeting.

   The AC-130 is operated by a crew of 11 - 13 men, depending on the variant. Cabin of the AC-130 is non-pressurized.

   The AC-130 gunships usually operate at night, because it is an easy target due to its large profile and low operating altitude. When engaging the target this aircraft operates at an altitude of just 1.1 - 2.5 km.

Variants

   AC-130A Spectre. It is an original version. A total of 19 aircraft were converted to this standard from C-130A Hercules transports. These were armed with four 7.62-mm GAU-2/A miniguns and four 20-mm M61 Vulcan cannons. In 1975 all of these aircraft were transferred to Air Force Reserve and were finally retired in 1995.

   AC-130E Spectre. It was introduced in 1969. A total of 11 aircraft were converted from the C-130E transports. These aircraft were armed with two 20-mm M61 Vulcan cannons, one 40-mm Bofors cannon and one 105-mm M102 howitzer. Later 8 or 10 of these aircraft were further upgraded to improved AC-130H standard.

   AC-130H Spectre. A total of 8 or 10 of these aircraft were upgraded from the earlier AC-130E configuration. This version was armed with two 20-mm M61 Vulcan cannons, one 40-mm Bofors cannon and one 105-mm M102 howitzer. It seems that after the year 2000 both 20-mm Vulcan cannons were removed. Last of these aircraft was retired in 2015.

   AC-130J Ghostrider. Is a new version, based on the MC-130J Combat Shadow II special operations tanker. This version made its first flight in 2014. It is armed with one 30-mm ATK GAU-23/A Bushmaster cannon, 105-mm M102 howitzer, AGM-176 Griffin, and AGM-114 Hellfire  missiles, GBU-39, GBU-44/B Viper Strike, and GBU-53/B bombs. It was planned that a total of 16 aircraft will be ordered.

   AC-130U Spooky II. It is an upgraded version This aircraft is armed with a 25-mm GAU-12 Equalizer cannon, one 40-mm Bofors cannon and one 105-mm M102 howitzer. Also it has increased ammunition capacity and improved fire control system. Currently 17 of these aircraft are operational with the USAF.

   AC-130W Stinger II. Is a new version. It is armed with one 30-mm ATK GAU-23/A Bushmaster cannon, AGM-176 Griffin, and AGM-114 Hellfire missiles, GBU-39, GBU-44/B Viper Strike, and GBU-53/B bombs. This version is currently in service with the USAF.