FMA IA 58 Pucará

The FMA IA 58 Pucará (Fortress) is an Argentine ground-attack and counter-insurgency (COIN) aircraft manufactured by the Fábrica Militar de Aviones. It is a low-wing two-turboprop-engined all-metal monoplane with retractable landing gear, and is capable of operating from unprepared strips when operationally required. The type saw action during the Falklands War and the Sri Lankan Civil War.

Development
In August 1966, Dirección Nacional de Fabricación e Investigación Aeronáutica (DINFIA), the Argentine state aircraft factory, began development of the AX-2, a Counter-insurgency (COIN) aircraft to meet a requirement of the Argentine Air Force. The chosen layout was a low-wing monoplane powered by two turboprop engines mounted in wing-mounted nacelles and fitted with a T-tail. In order to test the proposed layout, DINFIA first built a full-scale unpowered glider test vehicle, this flying for the first time on 26 December 1967.

Testing of the glider showed no major handling problems, and in September 1968, construction began on a powered prototype, given the designation FMA IA 58 Delfin, but later renamed Pucará, to be powered by a pair of 904 hp Garrett TPE331I/U-303 engines. (DINFIA had been renamed the Fábrica Militar de Aviones (FMA) earlier that year). The first prototype made its maiden flight on 20 August 1969, with a second prototype, with power switching to 978 shp Turbomeca Astazou XVIGs, following on 6 September 1970. The first prototype was later re-engined with the Astazou, with this engine being chosen for the production version, and a third, production, prototype followed in 1973. The first production model flew on 8 November 1974, with deliveries beginning in early 1976.

Design
The IA 58 Pucará is of conventional, all-metal (mainly duralumin) construction. The unswept cantilever wings have 7 degrees of Dihedral on the outer panels and are fitted with slotted trailing-edge flaps. The IA-58 has a tandem cockpit arrangement; the crew of two is seated under the upward opening clamshell canopy on Martin-Baker Mk 6AP6A zero/zero ejection seats and are provided with dual controls. Armour plating is fitted to protect the crew and engines from hostile groundfire. The aircraft is powered by a pair of Turbomeca Astazou engines, driving sets of three-bladed Ratier-Forest 23LF propellers; the propellers are also capable of being used as air brakes.

The Pucará was designed for operations from short, rough airstrips. The retractable tricycle landing gear, with a single nosewheel and twin mainwheels retracting into the engine nacelles, is therefore fitted with low pressure tyres to suit operations on rough ground, while the undercarriage legs are tall to give good clearance for underslung weapon loads. Three JATO rockets can be fitted under the fuselage to allow extra-short take-off. Fuel is fed from two fuselage tanks of combined capacity of 800 L and two self-sealing tanks of 460 L in the wings. The undercarriage, flaps and brakes are operated hydraulically, with no pneumatic systems.

Fixed armament of the Pucará consists of two Hispano 804 20 mm cannons mounted under the cockpits with 270 rounds each and four 7.62 mm Browning machine guns mounted on the sides of the fuselage with 900 rounds each. Three hardpoints are fitted for the carriage of external stores such as bombs, rockets or external fuel tanks, with one of 1000 kg capacity mounted under the fuselage and the remaining two, of 500 kg capacity beneath the wings. Total external weapons load is limited to 1620 kg. Onboard armaments are aimed by a simple reflector sight.

Operational history
The first units were delivered in May 1975 to the Argentine Air Force (Fuerza Aérea Argentina, FAA), equipping the 2° Escuadron de Exploration y Ataque, part of the 3rd Air Brigade (III Brigada Aérea) in northern Reconquista, Santa Fe province. They had their operational debut late in 1976, when a number of Pucarás carried out counter insurgency strikes from Córdoba against Communist ERP guerillas in Tucumán Province as part of Operativo Independencia.

1982 Falklands war
By the time of the Falklands War (Guerra de las Malvinas), about 60 Pucarás had been delivered As one of the few aircraft the Argentine service capable of flying operationally from the small airfields in the Falklands, with the runway at Port Stanley Airport was not long enough for FAA Skyhawks and Mirages to be deployed, it was decided to deploy a number of Pucarás to the Falklands, with four arriving at Port Stanley on 2 April 1982, with a further 8 arriving on 9 April. Many of the Pucarás remaining on the mainland were moved to Puerto Santa Cruz or Comodoro Rivadavia in southern Argentina where they were closer to the Falklands if needed for reinforcements, and were used to perform coastal surveillance.

Most aircraft used in combat were armed with unguided bombs, 2.75 inch rocket pods, or 7.62 mm machine gun pods. Pucarás operated from Port Stanley airport and two small grass improvised airfields at Goose Green and Pebble Island. They were used in the reconnaissance and light-attack role.

Three Pucarás were destroyed and one of their pilots killed at Goose Green by cluster bombs dropped by 800 NAS Sea Harriers on 1 May 1982. Six more were destroyed in the SAS Raid on Pebble Island on 15 May 1982.

On 21 May a Pucará was lost to a Stinger SAM fired by D Squadron SAS (the first Stinger launched in combat) and another to 30 mm cannon rounds from Cmdr Nigel "Sharkey" Ward's RN Sea Harrier, the latter after leading a successful two-aircraft raid on a shed allegedly used as an observation post by British forces. The aircraft was surprisingly tough, as Ward observed no less but 20 cannon hits before the target started to fall to the earth. The other Pucará, piloted by Lt. Micheloud, made good its escape after being chased by Lt. Cmdr. Alan Craig's Sea Harrier. Major Tomba, the pilot of the aircraft shotdown by Cmdr Ward, survived the ejection and was recovered by friendly forces.

Two Pucarás shot down a Royal Marines Scout helicopter with 7.62 mm machine gun fire on 28 May, while it was on a casualty evacuation mission during the battle of Goose Green. This was the only confirmed Argentine air-to-air victory of the war. One of these Pucarás crashed into Blue Mountain on the return flight to Port Stanley and was destroyed—the body of the pilot (Lt. Gimenez) was not found until 1986, and was buried with military honours at Port Darwin by his family, the first Argentine relatives to visit the Falklands since the end of the war. Also on the 28 May 2 PARA shot down a Pucará with small arms fire after it launched rockets on British troops (without causing any casualties), during the Battle of Goose Green. Lt Cruzado ejected and became a POW.

Captured aircraft
After the Argentine surrender eleven Pucarás (four of them in flying condition) were captured by British forces. Six were taken back to the United Kingdom, as follows:
 * A-515 (ZD485) – Royal Air Force Museum Cosford.
 * A-517 – Privately owned. Possibly shipped to the Channel Islands.
 * A-522 (8768M) – North East Aircraft Museum (on loan from the Fleet Air Arm Museum, Yeovilton).
 * A-528 (8769M) – Norfolk and Suffolk Aviation Museum (on loan from Museum of Army Flying, Middle Wallop).
 * A-533 (ZD486) – Boscombe Down Aviation Collection (Cockpit Section only).
 * A-549 (ZD487) – Imperial War Museum Duxford.

Sri Lankan Civil War
Some Pucarás were used in Sri Lanka counter-insurgency operations from 1993 to 1999; three were destroyed during combat sorties. In July 1995, during fierce fighting in the Northern Province, near Jaffna, Tamil Tiger rebels downed a Sri Lankan Air Force Pucará, the pilot was killed.

Upgrades
On May 1982, at the peak of the Falklands War, the Argentine Air Force, in collaboration with the Navy, outfitted a prototype, AX-04, with pylons to mount Mark 13 torpedoes. The aim was its possible production as torpedo-carrying aircraft to enhance the anti-ship capabilities of the Argentine air forces. Several trials were performed off Puerto Madryn, over Golfo Nuevo, but the war was over before the technicians could evaluate the feasibility of the project.

In 2007 an IA-58 of the Fuerza Aérea Argentina was converted to carry a modified engine operating on soy-derived bio-jet fuel. The project, financed and directed by the Argentine Government (Secretaría de Ciencia Tecnología e Innovación Productiva de la Nación), made Argentina the second nation in the world to propel an aircraft with biojet fuel. The project intends to make the FAA less reliant on fossil fuels.

Variants

 * AX-02 Delfin: Prototype.
 * AX-04: A torpedo-carrying prototype.
 * IA-58A Pucará: Two-seat counter-insurgency, close air support, attack aircraft. Main production version.
 * IA-58B Pucará Bravo: Modified two-seat counter-insurgency aircraft, with deeper forward fuselage, allowing the 20 mm Hispano cannon to be replaced by two 30 mm DEFA cannons, and with more advanced avionics. One prototype aircraft converted from IA-58A first flew on 15 May 1979.
 * IA-58C Pucará Charlie: Single-seat version designed to take advantage of lessons learned during the Falklands War, with increased capability in anti-shipping and anti-helicopter missions. Forward cockpit removed, with additional 30 mm DEFA cannon supplementing existing gun armament, and capability to carry Martin Pescador air-to-surface missiles underwing. Increased armour protection fitted, and better avionics. Single prototype converted, flying on 30 December 1985, but plans to convert more for the Argentine Air Force abandoned in 1988.
 * IA-58D Pucará Delta: Modernisation of existing IA-58A airframes, featuring new avionics systems and 950shp PT6A-62 Pratt & Whitney engines.
 * IA-66: Modification of IA-58A powered by two 1,000-ehp (746-kW) Garrett TPE331-11-601W turboprop engines. Single prototype converted from IA-58A flew in 1980.

Current operators

 * Argentine Air Force
 * Argentine Air Force
 * Uruguayan Air Force
 * Uruguayan Air Force

Former operators

 * Colombian Air Force
 * Sri Lanka Air Force (1993–1999, 2 shot down, 1 crashed, 1 retired)
 * Royal Air Force (A captured Pucara was evaluated at A&AEE Boscombe Down after the Falkands conflict before being donated to the RAF museum).
 * Sri Lanka Air Force (1993–1999, 2 shot down, 1 crashed, 1 retired)
 * Royal Air Force (A captured Pucara was evaluated at A&AEE Boscombe Down after the Falkands conflict before being donated to the RAF museum).
 * Royal Air Force (A captured Pucara was evaluated at A&AEE Boscombe Down after the Falkands conflict before being donated to the RAF museum).