In the late 1970s, it was becoming clear that the Italian Air Force was in need of a dedicated ground attack aircraft to replace its G.91s and to supplement the MB.326 trainer/light attack aircraft. What was sought was something that was dedicated to ground attack from the initial design and not just a made-over trainer. Around this same time, the Brazilian government was seeking a new attack aircraft as well.

In Italy, AerItalia and AerMacchi came to an agreement on an upcoming design to be called the AMX.  A few years later, in 1981, Embraer of Brazil joined in with the two Italian companies as the AMX was just what they were looking for to fulfill their attack aircraft requirements. An agreement for 187 Italian and 79 Brazilian aircraft was reached with the two Italian companies paying about 70% of the costs. As in all these multi-national aircraft builds, each company was responsible for certain sections of the aircraft, which were then sent to the appropriate locale for complete assembly.

Six prototypes were built, two of them being built and tested in Brazil. The first prototype, MM X594, first flew on May 15 1984 in Italy. Fifteen days later, it was lost due to a failure in the Rolls Royce engine. An additional prototype was built to replace it. By 1986, all Italian and Brazilian prototypes were flying and undergoing the usual rigorous testing. It was then decided that a two-seat trainer wouldn't be a bad idea and the contract was so modified to include this aircraft type, called the AMX-T

The AMX-T is a twin seater, high performance transonic turbofan jet, specifically developed for Advanced and Fighter Lead-In Training. It maintains the operational characteristics of the AMX - Ground Attack Fighter - already in operation with the Brazilian (FAB) and Italian (AMI) Air Forces. It is a high subsonic trainer with a low level dash speed in excess of 500 kt in any armed configuration. The AMX-T was selected by the Venezuelan Air Force (FAV) to replace the old and venerable T-2A Buckeyes in the advanced training phase.

AMX is a aircraft with shoulder-mounted wings, swept-back at 27.5°, with the engine air intakes placed in the top half of the fuselage, behind the cockpit. The pilot sits down in high position, offering a good view around the airplane. The tail is of traditional design, with the single fin and mobile elevators being similar to those of the Tornado. An in-flight refueling probe, equipped with a spotlight at the base of the probe, may be installed by the right side of the cockpit.

AMX is powered by a Rolls-Royce Spey RB.168 Mk.807 turbofan, of 11,030lb st, without afterburner. The Spey was originally designed in 1960 to equip the British carrier-based aircraft Hawker Siddeley Buccaneer (later on used by the Royal Air Force, having participated with distinction in the 1991 Gulf War). Other versions of Spey equipped the maritime patrol aircraft Hawker Siddeley Nimrod and the British FG.1 and FGR.2 versions of the McDonnell-Douglas Phantom II. More than 5,500 units were sold internationally; the version that equips AMX is tested and set up in Italy by FIAT/Piaggio and in Brazil by CELMA.

One of the main characteristics of the AMX is the existent redundancy in its electric, hydraulic and avionics systems. As all those systems are duplicated, with physical separation of certain elements as the cabling and actuators, it is expected that the aircraft is capable to complete the mission in case any of those systems suffer a failure. For example, in case the hydraulic system develops a fault, electric accumulators allow the operation of the landing gear, brakes and the front wheel, allowing for a smooth transition to the manual control of the elevators and ailerons.

AMX is also equipped with electronic counter measure devices, including flares and chaff dispensers, to disorient the action of infrared or active/semi-active guided missiles. For its self-defence, AMX is equipped with two air-air infrared guided missiles on wingtip rails as well as, in the Brazilian version, two DEFA 30mm cannons installed in the lower front fuselage (the Italian version carries a General Electric M61A1 Vulcan 20mm cannon, in the left lower front fuselage). Those cannons are also used in the ground-attack rôle, primary function of the aircraft.

In ground-attack missions, AMX may be equipped with conventional bombs (a typical load consists of six low-drag Mk. 82 type bombs), unguided rockets, laser-guided intelligent bombs, air-ground and anti-radar missiles and laser target designators. In the anti-surface ship rôle, AMX may also carry missiles such as the German MBB Kormoran 1 (previously used by the German Marineflieger Tornado squadrons) and the Aérospatiale AM39 Exocet, responsible for the sinking the HMS Sheffield destroyer and the Atlantic Conveyor container carrying merchant ship during the Falklands/Malvinas War, carried out by the crews of the Comando de Aviación Naval Argentina.

The Brazilian version of AMX will be equipped with a look-down/shoot-down multimode radar which will substantially enhance is combat capability. The AMX can easily operate from places with little infrastructure, due to its built-in auxiliary power unit (APU) which allows the start-up of its turbine and other systems. Its reinforced landing gear as well as the Speys power all combine to ease the take-off and landing on unprepared runways (the distance for take-off weighing 10,500Kg is of approximately 760m).