Northrop F-5 F-5A Freedom Fighter

The F-5A is the production form of the N-156F, the lightweight fighter Northrop developed as a private venture under Edgar Schmued, previously chief designer of the P-51 Mustang and the F-86 Sabre. The programme began with an order for three prototypes on 25 February 1958, aimed at a low-cost fighter that could be supplied under the Military Assistance Program to less-developed nations. The first N-156F flew at Edwards Air Force Base on 30 July 1959 and exceeded the speed of sound on that first flight.

Official interest waned quickly and by 1960 the programme looked like a failure. It revived in 1961, when the United States Army tested the type alongside the Douglas A-4 Skyhawk and the Fiat G.91, and decisively in 1962: the Kennedy Administration reinstated the requirement for a low-cost export fighter and on 23 April selected the N-156F as winner of the F-X competition. The F-5A designation came from the 1962 Tri-Service designation system and the production order followed in October. The Royal Norwegian Air Force placed the first international order on 28 February 1964.

Northrop manufactured 624 F-5As, including the three YF-5A prototypes, before production ended in 1972. Alongside them came 200 F-5B two-seat trainers, which lacked nose cannon but were otherwise combat-capable, and 86 RF-5A reconnaissance aircraft fitted with four-camera noses. Canadair built 240 first-generation F-5s under licence in Canada and CASA built 70 more in Spain. The F-5A had no radar as delivered, a trait consistent with its role as a simple day fighter; upgrade packages later fitted the AN/APQ-153.

The F-5 entered service with the USAF's 4441st Combat Crew Training Squadron at Williams Air Force Base on 30 April 1964, training aircrew and ground crew for customer nations including Norway. At that point the type was not intended for significant USAF use. Preliminary combat evaluation of the F-5A began in mid-1965 at Eglin Air Force Base under the code name Project Sparrow Hawk, and in October 1965 the USAF opened a five-month combat evaluation named Skoshi Tiger: twelve aircraft delivered to the 4503rd Tactical Fighter Squadron, modified with probe-and-drogue refuelling equipment, armour and improved instruments, and redesignated F-5C.

Over six months they flew more than 2,600 sorties from Bien Hoa Air Base over South Vietnam and from Da Nang Air Base over Laos. One aircraft was lost in combat with its pilot. Operations were rated a success, the F-5 being judged as capable a ground-attack platform as the F-100 albeit with shorter range, but the programme was more a political gesture to aid exports than a serious bid for US service. From April 1966 operations continued under the 10th Fighter Squadron, Commando, with the fleet raised to 17 aircraft and a further 7,300 sorties flown; between both units nine aircraft were lost in Vietnam, seven to enemy ground fire. In June 1967 the survivors were transferred to the Republic of Vietnam Air Force.

Following Skoshi Tiger, the Philippine Air Force acquired 23 F-5A and B models in 1965, which together with remanufactured Vought F-8 Crusaders eventually replaced its F-86 Sabres. Spain announced its choice of the F-5 on 11 January 1965 to replace its T-33s and F-86s: 70 airframes, 62 of them licence-built by CASA at Getafe. Taiwan received its first seven F-5As and two F-5Bs under the Military Assistance Program in 1965 and by 1971 operated 72 F-5As and 11 F-5Bs; during 1972 the United States borrowed 48 Taiwanese F-5As to lend to the Republic of Vietnam Air Force.

The F-5A was also the basis of Turkey's F-5/2000 programme, which upgraded F-5A/B and NF-5A/B airframes into lead-in trainers for the F-16C/D with a structural rework and new avionics, including a datalink, HUD, multifunction displays, HOTAS, radar warning receiver and a GPS/INS system.