When Pigs Fly: The A-10 “Warthog” and the Future of CAS


    The A-10 is the world’s premier close air support aircraft, but it is aging and the Air Force needs a replacement in the long term.

    There are few images which can evoke the sensation of sound more so than the following below.

    An A-10 Thunderbolt II from the 355th Fighter Squadron at Eielson Air Force Base, Alaska, fires a 30mm GAU-8 Avenger seven-barrel Gatling gun over the Pacific Alaska Range Complex. (U.S. Air Force photo/Airman 1st Class Jonathan Snyder)

    Anyone who has viewed footage of the A-10 Warthog in action can immediately call upon the telltale sound of a GAU-8 Avenger 30mm mini-gun ejecting 3,900 armor piercing incendiary rounds a minute. The A-10 Thunderbolt, or Warthog, is so called because of its jarring, perhaps even ugly appearance. But what the A-10 lacks in aesthetics, it more than makes up for in operational capability and engineering prowess. It is a quintessential piece of American aviation and the US Air Force’s primary delivery mechanism of close air support (CAS). 

    1. So What?

    The Air Force constantly insinuates that the Warthog is nearing the end of its operational lifespan. In fairness, the aircraft is over 50 years old. In 2015, Air Combat Command issued a press release announcing the intention of developing a replacement aircraft capable of fulfilling CAS mission profiles. Yet, in 2016, those plans were put on hold until 2022. The very next year, the Air Force announced that the A-10 would remain in the military’s inventory “indefinitely” [source]. Try as they might, military planners cannot seem to shake the Warthog. To use a famous American adynaton, the Warthog will retire when pigs can fly. 

    Hyperbole aside, the perpetual noises coming from Washington suggest that the A-10 faces replacement. The question remains as to what the Warthogs’ replacement will look like. Speculation abounds online over a potential stealth variant, or simpler airframe, such as the AT-6 Wolverine or T-29 Super Tucano. In any case, the prevalence of low intensity insurgencies across the world, and America’s potential involvement in such conflicts, mean that some form of CAS aircraft is well in the works for the US Air Force. 

    2. What is CAS?

    Close air support is as simple as the name would suggest. When enemy fire pins down a military unit, the select method for breaking through the enveloping fires is air support. Many types of aircraft and ordnance can achieve this. This does not mean, however, that any offensive ordnance dropped by an aircraft would count as close air support. A B-52 Stratobomber can absolutely saturate a battlefield with explosive munitions, but it is highly likely that friendly forces will perish in the onslaught of bombs. It is akin to using a tank or artillery shell as a sniper round. The point of CAS is to provide proximate areal fire to enemy positions in close relativity to friendly forces, without subjecting those friendly forces to unnecessary danger [source]. 

    It is perhaps helpful to consider CAS for what it isn’t. Air Interdiction, or deep air support (AI-DAS), is the targeting of enemy ground forces far behind enemy lines as a preventive tactic of delaying infantry or armored columns from advancing. The chief difference between DAS and CAS is the position of friendly ground forces. In CAS, friendly forces are already engaging the enemy force on the front line. They can achieve CAS through practically any sort of weapons system, even unguided bombs or rockets [source]. 

    3. History of CAS

    To better understand the role and purpose of the Warthog, it is useful to examine the development of CAS aircraft over the last 100 years. Military aviation was born in a somewhat forgotten conflict over the deserts of North Africa. The Italo-Turkish War resulted in several milestones for military airpower, including the first aerial bombing, the first downing of an aircraft by small arms fire and the first night time operation in military aviation. The Italian campaign against Libyan insurgents was primarily a counter insurgency operation (COIN). In so far as CAS is concerned, the Italians actually made very little use of the doctrine [source]. 

    3.1 First World War

    The First World War totally revolutionized the role of aviation in conflict, from dog fighting to aerial bombardment. Unlike the Italian conquest of North Africa, military aviation was a feature of every major combatant’s combat doctrine. From multiple historical accounts, it appears the first instances of CAS occurred over the trenched landscape of the western front [source].

    An FE2B made by the Royal Aircraft Factory, one of the earliest aircraft used for CAS

    During the Interwar period, every major developed nation began serious efforts to refine and create a CAS doctrine for their air forces. The British greatly used CAS throughout the various colonial conflicts of the 1920s and 1930s, such as the Third Anglo-Afghan War and the war in Somaliland. The German Luftwaffe also showed the value of CAS during the Spanish Civil War [source].

    3.2 Second World War

    The Second World War resulted in an enhanced appreciation for the need for ground attack aircraft operating with troops. The first person to truly realize that reality was Liddell Hart. Hart is the British military theorist who spent the latter half of the post-War period sanitizing the role of German Wehrmacht and mythologizing Erwin Rommel [source]. It is also very likely that Hart bears partial responsibility for the theory of fast moving combined arms offensives deep into enemy territory, otherwise known as “blitzkrieg”. Ultimately, it was Chief of the German General Staff, Heinz Guderian, who pioneered the blitzkrieg method in practice. Despite his apparent fascist sympathies, Hart duly noted the inability of stationary artillery units to provide adequate cover for advancing Allied troop formations. This would need to be remedied by either tanks for aircraft. Per an article which Hart published in the Daily Telegraph in 1926:

    “Offensive support must come from, and can only come effectively, from an even more mobile artillery moving immediately alongside. For this purpose the close co-operation of low-flying aircraft … is essential”.

    The Stuka

    Throughout 1939 – 1945, the USSR, US, Germany, Japan, Italy and Great Britain developed methods and aircraft for ground attack roles. The most famous of these aircraft is the Junkers Ju-87, better known as the Sturzkampfflugzeug, or Stuka. They built the Stuka for dive bombing, a technique the Germans mastered during the invasions of Poland and France [source]. Dive bombing was a far more accurate method of delivering bombs to ground targets. Horizontal bombing and glide bombing were far less accurate, and friendly fire was a real danger to friendly units. Since a major concern of close air support is the safety of friendly forces, dive bombing rapidly dominated the air-to-ground doctrines of every major combatant.

    A German Ju-87 Stuka (sourced from

    The Thunderbolt

    The United States first fielded the P-47 Thunderbolt in 1941. Moreover, the Thunderbolt soon became the choice aircraft for fighter-bomber roles in the Allied inventory. The P-47 was a fantastically durable aircraft. It could sustain incredible amounts of damage from enemy ground fire, flak or enemy fighters, and keep on flying. It could take direct hits to the engine and still make it back to its airbase to fly another day. This was because of the Pratt & Whitney R-2800 Double Wasp 18-cylinder air-cooled radial piston engine, operating at about 2,000 hp. The radial piston engine, unlike the Prestone, liquid-cooled engines in the Curtiss P-40 Warhawk [source].

    Republic P-47N Thunderbolt, the grandfather of the A-10 Warthog

    The liquid coolant system was essential for the P-40 to function. Without it, the engine would overheat and cease to be a functioning method of propulsion. This could quickly become a liability to the pilot. Even a single rifle round, piece of shrapnel or flak, could utterly devastate liquid-cooled engines. The P-47 could absorb ground fire and fly practically unaffected as it had no need for the coolant systems [source].

    3.3 From Korea to Vietnam

    A major step forward in the modern era of CAS was the introduction of the A-1 Skyraider in Korea and the AC-47 Spooky in Vietnam. Like the P-47, the A-1 was a bulky, durable aircraft capable of sustaining enormous amounts of ground fire. That, while remaining airborne despite absorbing rounds of critical components which might otherwise down a lesser aircraft.

    The Skyraider joined onto carrier air wings with the US Navy during the Korean War and, like the Vought F4U Corsair, fulfilled the role of a fighter-bomber. Its use aboard US Navy carriers continued well into the Vietnam War until it was replaced by the A-6A Intruder. The US generously donated the remaining A-1 Skyraiders left in its arsenal to South Vietnam to be used by US covert teams in Laos and Cambodia. By the end of the war, the US military had offloaded every single operational A-1 on the South Vietnamese, and South Vietnamese pilots came to rely heavily on the A-1 for every CAS mission [source].

    An AD-5W Skyraider on the deck of the USS Kearsarge (CVA-33) in 1958 (U.S. Navy National Museum of Naval Aviation photo No. 1996.253.2225)

    Like the A-10, the A-1 possessed an incredibly powerful engine, perhaps too powerful for its own good. The carrier-based variant of the Skyraider used by the Marine Corps, painted in a dark navy blue, was prone to “torque rolls”. The piston driven engine of the A-1 naturally spins a propeller to create thrust. Often, A-1’s on approach to a carrier could be “waved off”, or told to go around. This is essentially an aborted landing. In nearly every other aircraft, the standard procedure here is to apply additional throttle and speed up, and gain altitude. The incredible level of torque in the engines would betray the pilot. By adding far too much throttle, the pilot could place the aircraft into a torque roll, literally spinning the aircraft. This would cause a fatal descent into the ocean, likely ripping the airframe to shreds in the process [source].

    A Douglas A-1 Skyraider with the 602nd Special Operations Squadron over Vietnam, June 1970 (via USAF)

    4. The Warthog Takes Flight:

    Development of the A-10 began in September 1966 when the Air Force announced its intention to create a specially designed CAS aircraft [source]. The Pentagon issued a Requirements Action Directive (RAD) and opened the A-X program. The A-10, despite its widespread use during the War on Terror and COIN operations, is truly a product of the Cold War. This is reflected in the US Air Force’s request for a proposal mandating that the future CAS aircraft receive fitting with a 30 mm rotary gun. The Soviet Union’s armored units posed a serious concern to NATO military planners. Introducing new Soviet tank units and artillery further inflamed the necessity for an aircraft which could pulverize Russian tanks. 

    The A-X program was the first effort to develop a true-to-purpose and exclusive CAS platform, and the cannon was instrumental for that purpose. Two proposals, from Northrop Corporation and Fairchild Republic, landed the two companies competitive slots in the A-X program [source]. 

    4.1 Early Prototypes:

    Two prototype A-X aircraft underwent flight trials in 1973. The Air Force settled on Fairchild’s variant for a variety of reasons. The YA-10 prototype aircraft clearly struck the Air Force with its unique design and its far more powerful engines. Northrop’s YA-9 chose the Lycoming ALF 502 high bypass turbofan engines, whereas the YA-10 utilised the General Electric TF34 GE-100. By shirking on costs, the YA-9 ended up the less powerful variant. Beyond those limitations, the A-10 simply handled better than the YA-9. As such, the A-10 entered production in February 1976. Since 1976, the A-10 has experienced changes and upgraded into the variant we know today [source]. The Warthog even deployed to Eielson AFB near Fairbanks, Alaska, where it received a snow based paint scheme. They affectionally knew this variant as the “Snowhog” [source].

    The Northrop YA-9, the other major contender for the USAF CAS airframe

    4.2 The Warthog at War:

    The first deployment of the A-10 occurred in Operation Urgent Fury, of the United States Invasion of Grenada. As US Marines stormed the beaches of Carriacou in October of 1983, A-10s sharked the skies above. By all accounts, the A-10s did not engage any enemy ground targets or encounter air defence resistance [source]. The Warthog’s original purpose was to engage Soviet tanks in pitched battles along a defined line of contact, yet the collapse of the Soviet Union in 1991 was perhaps a blessing for the Warthog. 

    A Snowhog during exercise Cool Snow Hog ’82-1.

    Cannon Fodder

    During the YA-9 and YA-10 tests in the early 70’s, the GAU-8 cannon was yet to be fully completed. Instead, both planes flew with the M61A1 Vulcan 20 mm cannon. It is common to hear that the A-10 is a plane designed around a gun, but clearly, it is untrue [source].

    Perhaps realizing that the GAU-8 would require more engine power than the Vulcan, the Air Force strategically selected the A-10’s larger engines, but when the Air Force recieved the GAU-8, they put the gun to test immediately. Initial results were promising enough. However, whether the A-10 can take out a Russian tank in a combat environment is not a simple matter of point and shoot. A 1979 study conducted by the Naval Post Graduate School illustrated some glaring issues with the A-10’s CAS capabilities.

    Naval Findings

    They pitted the Warthog against several Soviet made T-62 tanks in low-angle-of attack strafing runs. The study found that the GAU-8 was only less than useful in frontal assaults. Soviet tanks, as well as most other tanks developed in the post-WWII era, are significantly more armored in the front as opposed to the rear of the vehicle. The GAU-8 could penetrate the T-62s when strafing from the rear or side [source].

    A less than ideal way to take on a Soviet tank with the A-10. (From the 1979 NPS study)

    Even if the GAU-8 cannot place every single round into the armor of the tank, the depleted uranium rounds can still wreak an incredible amount of damage. Several well-placed rounds will shred the tank suspension, treads, rollers and other external hardware. This may be enough to render the vehicle immobile and stationary, allowing infantry to close in and deploy anti-tank measures. This is essentially the purpose of CAS to begin with.

    4.3 Permissive Environments:

    The study highlights are major limitation of the A-10 in a combat environment. In “permissive” environments, such as in COIN operations where the opponent does not field armored columns or entrenched infantry positions, the Warthog is far more useful [source]. The War on Terror and the Iraq War were two permissive environments where the A-10 could perform exceptionally well. Yet, if the A-10 were to be placed against advancing Soviet or Russian battle formations, the Warthog would find itself hard pressed to render effective CAS. Suggestions that the United States transfers the A-10 to the Ukrainian military is a less than an intelligent proposal for this reason [source]. If the A-10 struggled to eliminate T-62 tanks in 1979, it would likely struggle to take out T-72 tanks in the Donbas.

    An A-10 conducts CAS in the Korengal Valley

    Not that the A-10 is totally useless. They used the Warthog throughout the War on Terror to great effect. Without question, the Warthog is a lethal weapon when used against the right targets and piloted by skilled airmen. During the Balkan Wars, for example, they used the A-10 extensively to destroy Serbian weapons caches and attacks armored vehicles.

    5. The A-10 over the Balkans:

    During the intervention on behalf of Kosovo and Bosnia, the United States conducted a majority of its policing action from the air. This effort would not have been possible without the Warthog. The A-10 became a veritable nuisance for the Serb forces, so much so that they began using decoys to throw off CAS pilots. The decoys seldom worked [source]. More to the point, Serbian anti-air systems were a real danger to A-10 pilots, and most flight time was spent avoiding or engaging anti-air defenses rather than seeking mobile armored targets. The Serbians began developing specific tactics to deal with the threat of the A-10, often concealing SAM batteries in undergrowth. According to Lt. Col. Chris “Kimos” Haave:

    The Serbs quickly learned that opening fire on Hogs with AAA or SAMs made them both obvious and high-priority tar- gets. Serb air defenses attempted to plan their missile and AAA shots to maximize the chances of hitting an A-10 while minimizing their own risks. The “SAM bush” was one such tactic. The Serbs would first fire AAA to make the A-10 jink. When they thought they had the pilot’s attention focused, they launched one or more SAMs in the hopes of scoring a hit. The SAM-bush had zero success, and often the A-10s made the Serbs regret they tried it.”

    A Serbian Tank from the perspective of a Warthog pilot, late 1990’s. This particular tanks has just been subjected to the GAU-8.

    A-10 pilots with the 40th Air Expeditionary Wing earned a slight legendary status throughout the duration of the Yugoslav Wars. They particularly enamored the enlisted garrison at the shared base of Gioia del Colle, Italy. Major Dawn Brotherton recounts the atmosphere at Gioia:

    At a home base, the support guys are rarely around when a jet lands, so they feel slightly removed from the mission. Not at Gioia!…Most of the time the pilots were more than willing to take the time to swap stories and play hero with the younger troops. It really built up camaraderie between the officers and enlisted folks…”

    5.1 The Unsinkable Airplane

    The Warthog is a marvel of engineering for a variety of reasons, but out of all the reasons the A-10 is an impressive aircraft, we can narrow these down to three primary categories:

    • The enormously powerful and resilient engines of the Warthog, each providing 9,065 lbs of thrust.
    • The titanic durability of the airframe, avionics and other smaller flight systems, able to withstand enormous punishment from ground fire.
    • A bristling array of weapons and ordnance capable of engaging practically any target.

    To begin with, the A-10’s power plant can reliably fly the aircraft on only one engine. In reality, the engines operate at half capacity while cruising, and throttle up when necessary [source]. The A-10 can reach a top speed of 420 mph, well in the subsonic range, but impressive considering the sheer amount of weapons carried by the aircraft. The GAU-8 itself is enormous. Without adequate ear protection, the GAU-8 can cause damage to the pilot’s hearing [source].

    The A-10 Minigun is practically the size of a small car

    Titanium Bathtub

    They built several features into the Warthog, which increases its survivability in the face of intense ground fire. Perhaps the most iconic of these features is the so called “titanium bathtub”. The bathtub is a unit of 1.5 inches thick titanium which encapsulates the bottom portion of the cockpit, protecting the pilot from bullets, shrapnel or the impact of a landing made without gear. The manufacturer crafts the canopy from bullet proof glass. During a training exercise in 2017, Capt. Brett DeVries was forced to land without his landing gear after a malfunction with the GAU-8 left portions of the cockpit damaged or exposed. He survived the crash-landing because of the bathtub. They salvaged the A-10 he piloted, and it returned to service, illustrating the hardiness of the aircraft [source].

    The A-10’s titanium bathtub (via the USAF)

    Capt. DeVries’ story is thankfully not unique. A-10 pilots over the Balkans reported similar stories of miraculous survivability. Major Phil Haun recounts a direct hit to his A-10 near Belgrade in 1999:

    I felt an incredible jolt to the aircraft on the right side. The nose tried to roll off to the right, and I had to put in full left rudder to keep her from flipping over. I was struggling at this point just to keep the jet flying. Dropping the nose, I started a gradual descent to maintain airspeed. My master-caution panel was lit up like a Christmas tree, and I finally looked over my shoulder to see the engine cowling blown off and the fan blades frozen. Sunlight streamed through the engine inlet. I made sure I was still headed towards the Macedonian border and returned my focus to keeping the jet under control.”

    Further Survivability Specifications

    Major Haun successfully landed his aircraft at Skopje. Throughout the First Gulf War, other A-10 pilots, faced with similar situations, survived those ordeals [source]. The A-10 boasts self-sealing fuel cells with internal/external foam. Even if the aircraft hydraulics system is inoperable, there are redundant manual back-up systems which allow the pilot the operate the aircraft. Also, the A-10s engine fans and gear are hardened, allowing it to take off from improvised runways where debris might damage critical flight components. More importantly, the A-10 can be easily serviced and repaired with limited facilities and its various parts are interchangeable [source].

    The A-10 has 11 external pylon hard points for a wide variety of munitions which complement its countermeasure and electronic warfare suite. The current iteration of the A-10, the A-10C, boasts a situational awareness datalinks (SADL), two new 5×5 inch multifunctional display made by Raytheon, a BAE integrated flight and fire control computer (IFFCC) and a Sniper XR targeting pod which is integrated with a sighting system built into the pilot’s helmet [source]. The Sniper XR pod itself contains FLIR and an IR marker and they upgraded the cockpit with a HUD alongside a HAVE-Quick secure communications system.

    Sniper Advanced Targeting Pod under a B-1B Lancer (via Staff Sgt. Darnell Cannady)

    The Future of CAS:

    The A-10 is an aging aircraft, nearing half a century old. It has received many upgrades over the last number of years, such as the “precision engagement upgrade program” which is expected to extend the Warthog’s service life until 2028. They recently tasked Boeing with replacing the wings of the US Air Force’s A-10 fleet [source]. Despite the extension of its service life, the aircraft will need to be replaced at a certain point in the next decade. The question is whether or not the A-10 will be replaced with a more advanced version of the aircraft.

    Anyone who has browsed online can find concept art of stealthy, futuristic A-10 concepts, but these are unlikely and a less than credible glimpse into the future of COIN/CAS operations. The F-35 could very well take on the role of the A-10, but the F-35 is an air superiority fighter. The purpose of COIN air operations is to deliver cost-effective CAS, and a $80 million aircraft is not the best candidate for that role.

    Congress has largely blocked the Air Force’s attempts to replace the A-10 with F-35s, despite the Air Force’s warning that the A-10 is not a suitable aircraft for the needs of the US Military in the Indo-Pacific [source]. Proposals to convert the A-10 into a stealth aircraft do not consider the enormous cost of coating an entire aircraft with radar absorbent material. Moreover, a stealth A-10 would need an internal weapons bay and could not support external cannon [source]. In reality, there is simply no good proposal to replace the world’s best CAS aircraft as of now.

    Cheap, propeller-driven aircraft that can efficiently conduct CAS may replace the A-10 soon. The Archangel ISR platform from IOMAX is a serious contender for that role. The AT-6 Wolverine and the AT-806 Sky Warden from L3Harris are also prime contenders. Many countries across Europe, Africa and the Middle East have already fielded these platforms [source]. These aircraft are durable, cheap and easy to use. They are excellent aircraft for permissive environments which were previously dominated by the A-10. Nevertheless, no aircraft since and likely soon will ever come close to the survivability, ingenuity and eminence of the Warthog.

    Alec Smith
    Alec Smith
    Alec Smith is a graduate of the MSC International Relations program of the University of Aberdeen and holds an LLB in Global Law from Tilburg University.

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