Compared with the F-5E, the F-20 was much faster, gained
beyond-visual-range air-to-air capability, and had a full suite of air-to-ground modes capable of firing most U.S. weapons. With these improved capabilities, the F-20 became competitive with contemporary fighter designs such as the
General Dynamics F-16 Fighting Falcon, but was much less expensive to purchase and operate.
Much of the F-20's development was carried out under a
US Department of Defense (DoD) project called "FX". FX sought to develop fighters that would be capable in combat with the latest
Soviet aircraft, but excluding sensitive front-line technologies used by the
United States Air Force's own aircraft. FX was a product of the
Carter administration's military export policies, which aimed to provide foreign nations with high quality equipment without the risk of US front-line technology falling into Soviet hands. Northrop had high hopes for the F-20 in the international market, but policy changes following
Ronald Reagan's election meant the F-20 had to compete for sales against aircraft like the F-16, the USAF's latest fighter design.
In the spring of 1977,
Jimmy Carter's administration had announced a new military export policy that limited sales of front line designs to countries within
NATO, along with Australia and Japan. Carter stated at the time that the U.S. could not be "both the world's champion of peace and the world's leading supplier of the weapons of war." Previously, there was no coherent export policy, fueling concerns that the US's latest technologies might quickly end up in Soviet hands.
South Korea's F-16 order was initially blocked under this policy
Carter personally blocked the sales of the F-5G to Taiwan
The Soviets continued to sell newer aircraft designs to their clients, placing allies of the U.S. at a disadvantage
Denied by the U.S., countries were turning to other vendors for modern fighters, notably France's
Dassault Mirage 2000
After a lengthy study, in January 1980, President Carter allowed the development of a new export fighter: FX.
General Dynamics (GD) responded to the FX requirement. GD's F-16/79 was a [downgraded] variant of the F-16A. Northrop responded with the F-5G
When
Ronald Reagan's administration took power in 1981, the export restrictions put in place by the Carter administration were slowly relaxed.
[16] At first, the FX program continued as normal, but a number of events eroded the value of the program and limit the F-5G's potential sales.
The signing of the 1982
US-PRC Joint Communiqué was a major agreement on arms sales, which continued blocking sales of the F-5G to Taiwan. By this point the Taiwanese had started their own light-fighter project, the
AIDC F-CK-1 Ching-kuo. In signing the Communiqué, the U.S. was signaling that Taiwan would not receive modern aircraft, therefore the Ching-kuo became Taiwan's primary focus. As a result, the F-5G's sales potential remained unestablished.
[17]
In the summer of 1982, Deputy Secretary of Defense
Frank Carlucci sent a memorandum to the Air Force and Navy, encouraging them to seek out potential foreign customers to procure FX aircraft.
[18] However, four months later Carlucci sent a classified memo to the same services to abandon the FX, and green-lighting the exporting of front-line fighters overseas.
[19] In December, after prompting from the White House, Carlucci reversed his position again, and directed the Air Force to fund a small number of F-20s in the fiscal year 1984 budget.
[20]
The future of the FX program seemed doubtful. Following an agreement to sell F-16s to Pakistan,
[21] Northrop felt that the F-5G needed to match the performance of F-16. This would require not only better performance from the engine, but a new and comparable avionics suite as well. Northrop saw that the F-5G was still being viewed as the "FX fighter", a low-cost option for second-tier air forces. To combat this perception, Northrop requested the designation "F-20"; the USAF approved in late 1982, and of the name
Tigershark in March 1983.
[9][22]