How the AC-130 Became a Terror in the Sky

By Senior Airman Julianne Showaltercombined by FOX 52 -, Public Domain,
August 4, 2018 Topic: Technology Region: Asia Blog Brand: The Buzz Tags: VietnamVietnam WarVietnam War HistoryUS AirforceAC-130

How the AC-130 Became a Terror in the Sky

The fixed-wing AC-130 gunship started as a “Gooney Bird” and became a true weapon of war during the Vietnam conflict.

In September 1971, AC-119s began to be turned over to the South Vietnamese Air Force in preparation for the introduction of the latest model gunship, a converted four-engine C-130 cargo plane. The transfers were completed and Vietnamese crews were fully trained by May.

AC-130A Prototype Arrives for Testing

In September 1967, the first AC-130A prototype arrived at Nha Trang Air Base and began its test program. Like its predecessor, the AC-119, the AC-130A carried four miniguns; in addition, it was equipped with four 20-mm cannon with 2,500 rounds of high-explosive incendiary ammunition, advanced electronics sensors, fire control systems, and searchlights.

Among the advanced technology on the AC-130A was the NOD, side-looking and forward-looking radar, and two steerable 20-kilowatt, variable-beam xenon arc illuminators (spotlights), capable of producing up to 1.5 million candle-power.

The AC-130A prototype test program ended on December 12, 1967. The final evaluation stated that the AC-130 had three times the combat effectiveness of the AC-47. The AC-130A gunship’s principal advantages were more power (four engines), more cargo space, and more cargo-carrying capability. These advantages permitted the AC-130 to have more and larger armament, more ordnance, and more speed.

The prototype AC-130A was sent back to the States for refurbishing but was returned to Vietnam in February of 1968, to begin flying combat missions along the Ho Chi Minh Trail.

From February to November, the AC-130A prototype destroyed 228 enemy trucks, damaged 133, and destroyed nine enemy sampans.

The AC-130A prototype flew its last mission on November 18, 1968, and was returned to the States once more. During its short combat career, the prototype was determined to be the most cost-effective close-support and interdictive craft in the U.S. Air Force arsenal.

Six “Spectre” Gunships in Southeast Asia

By the spring of 1969 there were six AC-130A “Spectre” gunships operating in Southeast Asia. In December 1969, a newly modified AC-130 gunship arrived at Ubon Air Base. Dubbed “The Surprise Package,” the new model sported two 20-mm rapid-firing Vulcan cannon, two 40-mm Bofors cannon, and advanced electronics.

During its 38-day combat evaluation, the Surprise gunship destroyed 178 enemy trucks, damaged 63 others, and logged 37 vehicles as “results not observed.” In addition, it attacked three antiaircraft sites, destroying one and causing major explosions at the other two. The new gunship was determined to be twice as effective in its interdiction role as previous models.

The resulting advanced model was designated the AC-130E, and began arriving at Ubon AFB in Laos during October 1970. Between November 1970 and January 1971, six more “E” model gunships arrived in SE Asia.

In the summer of 1971, six AC-130E gunships were produced with an advanced fire-control computer, higher gross weight limit, and improved countermeasure electronics. In addition, a flare-launching system equipped with 24 chaff flares to counter SAMs (Surface-to-Air Missiles) was installed.

Before the addition of the flare launcher, the crews of gunships had only two crude but innovative defenses against the heat-seeking SA-7 Strela missiles commonly used by the enemy. The first was for a crewmember to manually fire a handheld flare directly at an oncoming missile while hanging out the open rear cargo bay ramp. The tactic was meant to confuse the missile’s infrared tracking system by giving it another “hot” target to lock onto; sometimes it worked, sometimes it didn’t. The main problem was, you usually only had one shot.

The second defense against heat-seeking SAM attacks was for the pilot to bank the craft in such a way that the gunship’s wing would shield its engine’s heat signature from the oncoming missile. Neither tactic was effective against more advanced radar-guided missiles, however. As suspected, the flare-launching system was a great improvement over both previous tactics.

Gunships Destroy, Damage 10,000 Enemy Vehicles

During the winter campaign of ’71 to ’72, gunships destroyed or damaged over 10,000 enemy vehicles, destroyed 223 watercraft, and damaged 142 others. Most gunship activity in 1972 countered assaults by Communist forces on fire-support bases and provided fire support for troops.

In February 1972, the first AC-130E Spectre was outfitted with a 105-mm Howitzer in place of one of the 40-mm Bofors cannon. This gave the gunship a much greater firing range and allowed it to fire from a higher altitude. The addition of the Howitzer also made the gunship a much more effective spotter aircraft.

The ground explosion from the 6.5-pound artillery shell was much easier to spot by escorting jet fighter-bombers carrying napalm. F-4 jets often accompanied gunships on missions; three was the usual complement. This allowed two jets to stay with the gunship at all times, while one left for refueling by air tanker. The combination was very effective at suppressing antiaircraft fire.

The truce of January 1973 ended American gunship operations in Vietnam and Laos. The last combat mission for American gunships was flown over Cambodia on August 15, 1973. Unquestionably gunships played a vital role in America’s efforts in Vietnam and were responsible for saving thousands of American lives.

The Gunship Post-Vietnam

The end of the Vietnam War did not mean the end of the gunship, however. It has been an active participant in defending American ground and air forces in Grenada, Panama, Operation Desert Storm, Somalia, and Bosnia.

During the Granada invasion of October 1983, AC-130s suppressed enemy air-support systems and attacked ground forces, according to the Air Force. Gunships were especially helpful during the assault on the Point Salines Airfield.

In Panama in 1989, gunships destroyed the Panamanian Defense Force Headquarters and numerous command and control facilities by what the Air Force called a “surgical employment of ordnance in an urban environment.”

During Operation Desert Storm, Spectre gunships provided close-air support for ground forces and defended air-base installations against enemy attack.

During operations Continue Hope and United Shield in Somalia in 1992–1995, Spectre gunships flew reconnaissance missions and helped defend NATO ground forces. In recent years, Spectre gunships have provided support for NATO ground forces in Sarajevo.

Major Modifications, Upgrades to the Spectre Gunship

Since the end of the Vietnam War, the AC-130 Spectre gunship has undergone several major modifications and upgrades in its performance, armament, and electronics. The latest version is the AC-130U.

This air-to-ground attack aircraft features advanced armament with new computer- directed gun systems. No longer stationary, or fixed-mounted, the guns now have computer-driven, trainable mounting systems, integrated with fire-control avionics. These advanced fire- control systems are fed target coordinates from infrared and radar sensors.

Two 20-mm Vulcan cannon have been replaced by one General Electric GAU-12/U 25-mm Gatling gun. The new gun can fire five rounds per second, has greater range, has a much more powerful projectile, and is much more accurate than the 20-mm Vulcans. Other armament includes one 40-mm Bofors cannon with 256 rounds of ammunition, and one 105-mm Howitzer with a hundred rounds.

The new gunship can fire on two separate targets from an altitude of 20,000 feet, with a slant range of 25,000 feet (more than four nautical miles). This new capability greatly improves its standoff firepower and has improved its survivability.

The “U” also has an advanced array of sensors including forward- and side-looking radar, low-light television, infrared sensing devices (ISDs), a global positioning system (GPS), and inertial navigation systems. This gives the gunship, according to the Air Force, “a method of positively identifying friendly ground forces as well as effective ordnance delivery during adverse weather (and night) conditions.”

This article by Ron Sanders originally appeared on the Warfare History Network.

Image: Wikimedia Commons