Design
The A-10 has superior maneuverability at low speeds and altitude, thanks to straight, wide wings with downturned "droop" wing tips. These also allow short takeoffs and landings, permitting operations from rugged, forward airfields near front lines. The aircraft can loiter for extended periods of time and operate under 1,000 feet (300 m) ceilings with 1.5-mile (2.4 km) visibility. It typically flies at a relatively slow speed of 300 knots (345 mph or 555 km/h), which makes it a much better platform for the ground-attack role than fast fighter-bombers, which often have difficulty targeting small and slow-moving targets.
Engine exhaust passes over the aircraft's horizontal stabilizer and between the twin tails, decreasing the A-10's infrared signature and lowering the likelihood that the aircraft can be targeted by heat-seeking missiles. The placement of the engines behind the wings partially shields them from anti-aircraft fire. The leading edge of the mainplane is honeycomb to provide strength with minimal weight compromise. Honeycomb panels of this type on the A-10 include the flap shrouds, elevators, rudders and other sections of the fins.
The A-10 has integrally machined skin panels. Because the stringers are integral with the skin there are no join or seal problems. These panels, fabricated using computer controlled machining, reduce the time and hence the cost of production. Combat experience has shown that this type of panel is more resistant. The skin is not load-bearing, so damaged skin sections can be easily replaced in the field, with makeshift materials if necessary.
The ailerons are at the far ends of the wings to gain greater rolling moment as with most aircraft but there are two distinguishing features. First, the ailerons are larger than is typical, almost 50% of the chord, providing improved control even at slow speeds. The aileron is also split, making it a deceleron.
The Thunderbolt II can be serviced and operated from bases with limited facilities near battle areas. An unusual feature is that many of the aircraft's parts are interchangeable between the left and right sides, including the engines, main landing gear, and vertical stabilizers. The sturdy landing gear, low-pressure tires and large, straight wings allow operation from short rough strips even with a heavy ordnance load, allowing the aircraft to operate from damaged airbases. The aircraft is designed to be refueled, rearmed, and serviced with minimal equipment. Operating from a forward area is both useful for close air support and necessary due to the A-10's relatively low cruise and top speeds.
Because of the close proximity of the front landing gear and the A-10's main cannon, the landing gear is offset to the aircraft's right and cannon slightly to the left. During ground taxi, the offset front landing gear causes the A-10 to have dissimilar turning radii. Turning to the right on the ground takes less space than turning left
Durability
The A-10 is exceptionally hardy. Its strong airframe can survive direct hits from armor-piercing and high-explosive projectiles up to 23 mm. The aircraft has triple redundancy in its flight systems, with mechanical systems to back up double-redundant hydraulic systems. This permits pilots to fly and land when hydraulic power or part of a wing is lost. Flight without hydraulic power uses the manual reversion flight control system; this engages automatically for pitch and yaw control, and under pilot control (manual reversion switch) for roll control. In manual reversion mode, the A-10 is sufficiently controllable under favorable conditions to return to base and land, though control forces are much higher than normal. The aircraft is designed to fly with one engine, one tail, one elevator and half a wing torn off. Self-sealing fuel tanks are protected by fire-retardant foam. Additionally, the main landing gear is designed so that the wheels semi-protrude from their nacelles when the gear is retracted so as to make gear-up landings (belly landing) easier to control and less damaging to the aircraft's underside. They also are all hinged toward the rear of the aircraft, so if hydraulic power is lost the pilot can simply drop the gear and a combination of gravity and wind resistance will open and lock the gear in place.
The cockpit and parts of the flight-control system are protected by 900 pounds (408 kg) of titanium armor, referred to as a titanium "bathtub".[17] The tub has been tested to withstand strikes from 23 mm cannon fire and some strikes from 57 mm rounds.[17] It is made up of titanium plates with thicknesses from ½ inch to 1½ inches determined by a study of likely trajectories and deflection angles. This protection comes at a cost, though; the armor itself weighs almost 6% of the entire aircraft’s empty weight. To protect the pilot from the fragmentation likely to be created from impact of a shell, any interior surface of the tub that is directly exposed to the pilot is covered by a multi-layer Kevlar spall shield. The canopy consists of a bullet-proof diffusion-bonded stretched-acrylic to withstand small arms fire and is resistant to spalling. The front windscreen offers shielding resistant to 20 mm cannon fire.
Recent proof of the durability of the A-10 was shown when then-Captain Kim Campbell, USAF, flying a ground support mission over Baghdad during the 2003 invasion of Iraq, suffered extensive flak damage to her A-10. Enemy fire damaged one of the A-10's engines and crippled its hydraulic system, forcing the back-up mechanical system to operate the aircraft's stabilizer and flight controls. Despite this, Campbell managed to fly it for an hour and landed it safely at the air base in manual reversion mode.
Powerplant
USAF Thunderbolt taxiingThere are several reasons for the unusual location of the A-10's General Electric TF34-GE-100 turbofan engines. First, the A-10 was expected to fly from forward air bases, often with semi-prepared substandard runways that presented a high risk of foreign object damage to the engines. The height of the engines lowers the chance that sand or stones will enter the inlet. This also allows engines to remain running, allowing for shorter servicing and rearming turn-around times by ground crew. Servicing and rearming are further helped by having wings closer to the ground than would be possible if the engines were wing-mounted. The position also reduces the IR signature further, which is already low due to the engines' 6:1 bypass ratio. Because of their high position, the engines are angled upward nine degrees to bring the combined thrust line closer to the aerodynamic center of the aircraft. This avoids trimming measures to counteract a nose-down pitching moment if the engines were parallel to the fuselage. The heavy engines require strong supports, so their pylons are connected to the airframe by four bolts.[18]
All four fuel tanks are near the center of the aircraft, reducing the likelihood that they will be hit or separated from the engines. The tanks are protected by several measures. The tanks are separate from the fuselage; thus, projectiles would need to penetrate the skin before reaching the tank. The refueling system is purged after use so that there is no fuel unprotected anywhere in the aircraft. All pipes self-seal if they are compromised. Most of the fuel system components are inside the tanks so that if a leak were to occur from the component the fuel would not be lost. If a tank does get damaged, check valves ensure that fuel does not flow into the compromised tank. Most importantly, reticulated polyurethane foam lines both the inner and outer sides of the fuel tanks, holding debris and restricting fuel spillage in the event of damage. The other source of possible combustion, the engines, are shielded from the fuel system and the rest of the airframe by firewalls and fire extinguishing equipment
Weapon systems
Although the A-10 can carry considerable disposable stores, its primary built-in weapon is the 30 mm GAU-8/A Avenger Gatling gun. One of the most powerful aircraft cannons ever flown, it fires large depleted uranium armor-piercing shells. In the original design, the pilot could switch between two rates of fire: 2,100 or 4,200 rounds per minute; this was changed to a fixed rate of 3,900 rounds per minute. The cannon takes about half a second to come up to speed, so 50 rounds are fired during the first second, 65 or 70 rounds per second thereafter. The gun is consistently accurate; it can place 80% of its shots within a 40-foot (12.4 m) circle from 4,000 feet (1,220 m) while in flight. The GAU-8 is optimized for a slant range of 4,000 feet (1,220 m) with the A-10 in a 30 degree dive.
The fuselage of the aircraft is built around the gun. For example, the nose wheel is offset to the right so that the gun's firing barrel at the 9 o'clock position is aligned on the aircraft's centerline. The gun's drum holds 1,174 rounds of 30 mm ammunition, a reduction from the 1,350 rounds carried by early aircraft because of the susceptibility of the drum to damage during loading. The damage caused by rounds firing prematurely due to impact of an explosive shell would be catastrophic, so a great deal of effort has been taken to protect the 5 ft (1.52 m) wide, 9 ft (2.74 m) long drum. There are many armor plates of differing thicknesses between the aircraft skin and the drum, to detonate an incoming shell before it reaches the drum. A final layer of armor around the drum itself protects it from fragmentation damage. The gun is loaded by Syn-Tech's linked tube carrier GFU-7/E 30 mm ammunition loading assembly cart; a vehicle unique to the A-10 and GAU-8.
Another commonly used weapon is the AGM-65 Maverick air-to-surface missile, with different variations for either electro-optical (TV-guided) or infra-red targeting. The Maverick allows targets to be engaged at much greater ranges than the cannon, a safer proposition in the face of modern anti-aircraft systems. During Desert Storm, in the absence of dedicated forward-looking infrared cameras, the Maverick's infra-red camera was used for night missions as a "poor man's FLIR". Other weapons include cluster bombs and Hydra rocket pods. Although the A-10 is equipped to deliver laser-guided bombs, their use is relatively uncommon; at the low altitudes and speeds of typical A-10 operations, standard unguided bombs provide adequate accuracy at far lower cost. In any event, the guided weapons would provide little benefit, as there would be nearly no time for the weapons to steer onto a target. A-10s usually fly with an ALQ-131 ECM pod under one wing and two AIM-9 Sidewinder air-to-air missiles under the other wing for self-defense.
Operational History
The first unit to receive the A-10 Thunderbolt II was the 355th Tactical Training Wing, based at Davis-Monthan Air Force Base, Arizona in March 1976. The first unit to achieve full combat-readiness was the 354th Tactical Fighter Wing at Myrtle Beach AFB, South Carolina in 1978. Deployments of A-10As followed at bases both at home and abroad, including England AFB, Louisiana, Eielson AFB, Alaska, Osan Air Base, South Korea, and RAF Bentwaters/RAF Woodbridge, England. The 81st TFW of RAF Bentwaters/RAF Woodbridge operated rotating detachments of A-10s at four bases in Germany known as Forward Operating Locations (FOLs): Leipheim, Sembach Air Base, Nörvenich, and Ahlhorn.
A-10s were initially an unwelcome addition to the arsenal in the eyes of Air Force brass. As the Air Force senior leadership became increasingly populated by general officers from the fighter community, the Air Force prized the high-flying, high-performance F-15 Eagle and F-16 Fighting Falcon fighter jets, and were determined to leave close air support primarily to Army helicopters.
The A-10 saw combat for the first time during the Gulf War in 1991, destroying more than 900 Iraqi tanks, 2,000 military vehicles, and 1,200 artillery pieces. A-10s shot down two Iraqi helicopters with the GAU-8 gun. The first of these occurred on February 6, 1991 when Captain Robert Swain shot down an Iraqi helicopter over Kuwait marking the A-10's first air-air victory. Four A-10s were shot down during the war, all by surface-to-air missiles. A-10s had a mission capable rate of 95.7%, flew 8,100 sorties, and launched 90% of the AGM-65 Maverick missiles fired in the conflict. Shortly after the Gulf War, the Air Force gave up on the idea of replacing the A-10 with a close air support version of the F-16.
In the 1990s many A-10s were shifted to the forward air control (FAC) role and redesignated OA-10. In the FAC role the A-10 is typically equipped with up to six pods of 2.75 inch (70 mm) Hydra rockets, usually with smoke or white phosphorus warheads used for target marking. OA-10s remain fully combat capable despite the redesignation.
A-10s again saw service in the 1999 Kosovo War, in the later stages of the 2001 war in Afghanistan, during Operation Anaconda in March 2002 and in the Iraq war (2003-present).
On 30 April 2003, United States Air Forces Central issued Operation Iraqi Freedom: By the Numbers, a declassified report about the aerial campaign in the conflict. Sixty A-10s were deployed in Iraq; one was shot down near Baghdad International Airport by Iraqi fire late in the campaign. Of the A-10s deployed, 47 were Air National Guard aircraft, and 12 were from the Air Force Reserve. The A-10 had a mission capable rate of 85% in the war, and fired 311,597 rounds of 30 mm ammunition. The A-10 also flew 32 missions in which the aircraft dropped propaganda leaflets over Iraq.
The A-10C first deployed to Iraq in the third quarter of 2007 with the 104th Fighter Squadron of the Maryland Air National Guard. The jets include the Precision Engagement Upgrade. The A-10C's digital avionics and communications systems have greatly reduced the time to acquire a close air support target and attack it.
The A-10 is scheduled to stay in service with the USAF until 2028 and possibly later, when it may be replaced by the F-35 Lightning II. The A-10 fleet is currently undergoing upgrades.
Kaore Ryu Akira Community Member 
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