From Vietnam to Afghanistan and the fifty years between, one piece of military hardware has continued to strike fear into those on the ground. Capable of circling a target ominously for hours on end and disgorging the kind of firepower that leaves Earth trembling, the Lockheed AC-130 is the dreaded colossus of the skies you really don’t want appearing above you.
This is about as close as you’re going to get to a floating fortress. It comes armed to the teeth, so much so they can’t even fire everything at the same time because of the massive recoil, and has on countless occasions saved the lives of those on the ground.
This is a ferocious ground attack gunship that is often used for close air support for troops on the ground and has battled valiantly in every major conflict since 1968, making it one of the most important aircraft in the U.S military.
The Vietnam War
As the Vietnam War progressed, it was clear to the Americans that the fighting would be very different from almost every other conflict they had been involved in. The tactics used by Viet Cong often meant that troops on the ground required close and sustained air support. This led to a series of fixed-wing gunships that could provide more firepower than light to medium ground-attack aircraft while also remaining in the fight for significantly longer.
First up was the legendary Douglas AC-47, which was technically just a modified C-47 transport aircraft with guns added to fire out of the windows. It might sound rudimentary, and in many ways, it was because nothing quite like it had ever been used, but the AC-47 went on to excel during the Vietnam War and soon led to calls for purpose-built gunships.
Lockheed C-130 Hercules
Technically speaking, gunships weren’t new with the Boeing YB-40 Flying Fortress and Consolidated XB-41 both used during World War II as bomber escorts and the modified North American B-25 Mitchell often used to attack shipping in the Pacific. The word gunship essentially just means an aircraft with laterally mounted heavy armaments – in layman’s terms that translates as big guns that fire from the side. Whereas traditional bombers or attack aircraft would strafe targets, meaning they would pass over them repeatedly in a straight line, gunships were usually tasked with circling a target while hitting it again and again.
But before we get to the AC-130, we need to start with C-130 Hercules, a four-engine turboprop military transport aircraft that was introduced in 1956. Over the last 60 plus years, this has become the transport aircraft, operating in war zones but also often in humanitarian roles across the globe.
Today, it is the longest-running continuously produced aircraft in the U.S Air Force but to link it with our story today, we need to go back to Dayton, Ohio 1967.
Project Gunship II
With the success of the Douglas AC-47, the U.S Air Force was eager to expand the use of gunships and a program to convert an existing C-130 into an AC-130 got under the way at the Wright-Patterson Air Force Base in Dayton, Ohio, known as Project Gunship II.
Additions included a direct-view night-vision telescope, an early forward-looking infrared device along with miniguns and rotary cannons fixed to the left-hand side of the aircraft. A purpose-built analogue fire-control computer was devised by RAF Wing Commander Tom Pinkerton at the USAF Avionics Laboratory at Wright-Patterson AFB.
Early testing was carried out mainly at the Eglin Air Force Base in Florida with the first AC-130 deemed ready for combat testing in September 1967 and arrived at the Nha Trang Air Base in South Vietnam shortly after. Those in Vietnam must have liked what they had seen because seven more conversions took place in 1968, with a further 10 coming in 1970.
As you will probably imagine for an aircraft that was converted from another, the AC-130 and the C-10 Hercules share plenty of similarities. The AC-130 comes with a large crew of 13, five officers and eight enlisted men. The officer group includes the pilot, copilot, navigator, fire control officer and electronic warfare officer, while the enlisted men account for the flight engineer, TV operator, infrared detection set operator, loadmaster and four aerial gunners.
The aircraft is 29.79 metres (97 ft 9 in) long with a wingspan of 40.41 metres (132 ft 7 in) and has a maximum take-off weight of 70,307 kg (155,000 lb), which interestingly enough is almost exactly the same as NASA’s Space Shuttle.
This is a gunship that has very much been evolving over the last 50 years, with the first designated as the AC-130A Spectre, followed by the AC-130E Spectre, AC-130H Spectre and the AC-130U Spooky, all of which are now retired. The varieties still in operation are the AC-130W Stinger II and AC-130J Ghostrider. The unit cost of the newest aircraft is thought to be in the region of $165 million.
It comes with four engines, with the AC-130U version using the Allison T56-A-15 turboprop engine, with 4,300 shp and the AC-130J variety using the Rolls-Royce AE 2100D3 with its 4,700 shp. Both versions come with four-bladed constant-speed reversible propellers giving the AC-130 a top speed of 480 km/h (300 mph) and a maximum range of 4,100 km (2,500 miles) – which is roughly the distance from London to Cairo.
But let’s be honest here, the AC-130 is best known for the torrent of weaponry on board. Before we have a look at exactly what kind of firepower the aircraft has, it’s worth just reiterating the kind of combat it is typically involved in. This is a long-endurance aircraft capable of launching sustained attacks on a specific point on the ground using what is known as the pylon turn.
The pylon turn was first used during air races in the early 20th Century and essentially calls for an aircraft to circle a fixed point. To be considered a true pylon turn the aircraft’s wing has to remain pointed at the same spot on the ground. This technique can be used to relay messages or deliver supplies to the ground – or in the case of the AC-130, deliver sustained hellish fire on whatever its wing is pointed at. And it is because of this attack method that the AC-130’s main weaponry is located only on the left-hand side of the gunship.
When the aircraft was first converted in the late 1960s and early 1970s, they came with four 7.62 mm (0.3 inches) GAU-2/A miniguns and four 20 mm (0.7 inches) M61 Vulcan 6-barrel rotary cannons, but these were later updated to include two 20 mm (0.7 inches) M61 Vulcan cannons, one 40 mm (1.58 inch) L/60 Bofors cannon and one 105 mm (4.13 inch) M102 howitzer.
But that’s still relatively old school. The two variants still in operation today are the AC-130W Stinger II and the AC-130J Ghostrider, both of which come with one 30 mm (1.1 inches) ATK GAU-23/A autocannon, one 105 mm (4.13 inch) M102 howitzer, the ‘Gunslinger’ weapons system which can fire the AGM-176 Griffin missiles and/or GBU-44/B Viper Strike munitions and finally the wing-mounted, AGM-114 Hellfire missiles, GBU-39 Small Diameter Bombs (SDBs) and/or GBU-53/B SDB IIs.
So imagine all of that pouring down from the sky as this air leviathan circles around like an animal stalking its prey. It’s not hard to see why this gunship has become such an enormous success – well, for the Americans at least.
However, its brutal amount of weaponry does come with a few problems. First and foremost is the colossal recoil felt when all of those guns are pounding away together. The recoil from the 105mm (4.13 inch) howitzer is so great that it needs to have a protective cage around it to protect the gunner behind and to complicate things even more, the crew are careful not to fire the 105 mm (4.13 inch) and the 30 mm (1.1 inches) at the same time because of the enormous stress it places on the already strengthen airframe.
It’s also not exactly easy to control when you have all of that firepower pouring out and when you consider that the weaponry is situated on the left-hand side, the natural recoil when the guns are firing tends to push the nose to the right and out from the pylon turn that the pilot is trying to maintain.
Unlike most other modern military aircraft, the AC-130 relies on visual targeting but it comes with one of the finest sensor suits in the business to help those on board. The sensor suite combines a television sensor, infrared sensor, and radar to pinpoint targets on the ground, but also to visually or electronically identify friendly ground forces. It uses the AN/APQ-180, a synthetic aperture radar, for long-range target detection and identification as well as inertial navigation systems and a global positioning system. The combination of technology onboard, allows the AC-130 to attack two targets simultaneously.
The AC-130s swept into combat for the first time during the Vietnam War at the end of 1967. By this point, the U.S had been involved in major combat operations in the country for just over three years and the pressure to get the job done was enormous. Back home, anti-war protests were sweeping the nation as the number of boots on the ground in Vietnam rose past 500,000.
The North Vietnamese were proving themselves to be much more tenacious and resilient than perhaps the United States had expected and as U.S casualties rapidly rose and the Ho Chi Minh Trail grew in significance, the Americans had to find an answer and find it quickly.
While the AC-130 was never seen as the panacea to all the U.S’ woes in South-East Asia, it certainly provided something very different. The gunships’ ability to provide close and sustained air support proved invaluable to troops on the ground and certainly saved countless lives. The major problem with the AC-130s was that they were relatively easy targets for anti-aircraft fire and because of this most close air support missions took place at night or with air support during the daytime, often accompanied by the F-4 Phantom II.
Destroying the Ho Chi Minh trail became an obsession for the United States and understandably so. If you don’t know too much about this famed transportation route which snaked down from North Vietnam through Laos, Cambodia and finally into South Vietnam then you’re in luck because we’ve recently done an entire video on it here on Megaprojects. Quite simply, this was the lifeblood for Viet Cong attacks in the south and a constant, painful thorn in the side for the Americans and their allies.
The problem with Ho Chi Minh Trail was that nobody was exactly sure where it was. That might sound slightly unbelievable considering the full might and technological advantage of the Americans, but this was often met with pure ingenuity by the North Vietnamese. As the trail grew and became more sophisticated, large sections of it were virtually undetectable from the skies above, with carefully placed camouflage hiding the relentless transportation routes below. But the Americans had a trick up their sleeve.
During the war, several AC-130s were equipped with a magnetic anomaly detector system called Black Crow, a highly sensitive passive device with a phased-array antenna. Essentially the Black Crow system was used to detect deviations in the Earth’s magnetic field and while this technology was first used to find submerged submarines, it seemed equally adept at searching out the unshielded ignition coils located on the trucks travelling along the Ho Chi Minh Trail. This came to be known as ‘truck hunting’ and of the six AC-130s that were shot down during the war, four were downed while prowling for targets along the trail area. The U.S reported that more than 10,000 trucks were destroyed by AC-130s over the eight years they were in the country.
For the remainder of the Cold War, AC-130s took part in operations around the world. In Panama, one gunship was awarded the Mackay Trophy for the most ‘meritorious flight of the year’ after destroying the Panama Defense Force headquarters and numerous command-and-control facilities. The idea of giving out a trophy for successfully destroying targets and no doubt killing your enemy seems a little odd to me, but each to their own.
In 1979, following the storming of the U.S embassy in Tehran, several AC-130s were deployed to the area as the United States pondered its response. Retaliatory strikes within Iran were briefly considered, but gunships instead took part in the debacle that was Operation Eagle Claw, the failed U.S rescue attempt which ended in the deaths of 8 U.S servicemen.
Throughout the 1990s, AC-130s were involved in humanitarian operations across the globe, including Haiti, Somalia, Liberia, Albania and Yugoslavia. In 1990 and 1991, they were involved in the Gulf War and again proved to be indispensable to those on the ground. On 31st January 1991, a lone AC-130 chose to remain circling above the battlefield to protect the Marines below. It was eventually downed by a surface to air missile, killing all 14 onboard.
The 9/11 attacks ushered in a new era of conflict as the War on Terror began in earnest. AC-130s were heavily involved in both Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom. They played a key role in the early days of the war in Afghanistan and were used to hit Taliban targets called in by special forces on the ground.
In Iraq, the AC-130s were typically deployed as close air support, often above urban areas to combat insurgents on the ground. You can imagine what one of these monsters can do when circling above a town or city and their use came in for heavy criticism from human rights groups. But the most notorious incident involving an AC-130 came not in Iraq but Afghanistan.
On 3rd October 2015, an AC-130 approached a building in Kunduz in Afghanistan which sources had identified as housing enemy combatants and began unloading on it like only this kind of flying war machine can. Five times the AC-130 turned its fearsome arsenal on the shattered building below before finally heading home with a successful mission seemingly complete. But the building the gunship attacked had not contained any insurgents, far from it. The smouldering wreck was not at all an enemy target but rather a hospital run by Doctors Without Border. The attack killed 42 people in the hospital, with another 30 injured and remains one of the worst single incidents involving civilians to have occurred in Afghanistan.
A 3000-page report by the Americans set out the astonishing series of mistakes that led to the attack and 16 servicemen were eventually punished for their roles, though these were all internal and no criminal investigation was ever launched. It was made clear that at no point did those onboard the AC-130 or the special forces on the ground know that the building was a hospital and the tragedy was instead blamed on bad intelligence, a rush preflight briefing and an onboard problem with the satellite radio, which meant the crew could not upload the database or send and receive any other vital emails or information that could have helped prevent the incident. The attack in Kunduz was a sobering reminder of just how powerful these AC-130s are and just how bad things can go when their fearsome firepower is misdirected.
To get a sense of just how important the AC-130s have been over the years, you need only look at their revered status held by those on the ground they have so often protected. Their role in the Vietnam War may not have been enough to tip the conflict into the American favour, but they unquestionably played their part.
Their success in Vietnam has seen their use greatly expanded and now it would be unheard of for U.S troops to operate without AC-130s or other gunship varieties. These are unique monsters, not quite just an aircraft, not quite a helicopter, their ability to circle for hours above a target while coordinating with troops on the ground make them some of the most versatile and dependable machines at the U.S Air Force’s disposal.