Northrop F-5E Tiger 2000

The Republic of China Air Force became the world's largest F-5E/F user. The Aerospace Industrial Development Corporation (AIDC), successor to the air force's Aero Industry Development Center, had licence-built 242 single-seat F-5Es and 66 two-seat F-5Fs, 308 aircraft in all, between the rollout of the first F-5E on 30 October 1974 and the last delivery on 9 December 1986. In the 1990s, as the F-5E/F could no longer match modern fighters, several manufacturers began offering Taiwan upgrade packages for the fleet, and AIDC wanted to win that contract for itself.

The first attempt was made with the original manufacturer. AIDC and Northrop Grumman announced a joint programme called Tiger IV, intended to prepare the F-5 for 21st-century combat: an APG-66 radar like the F-16's, a new ejection seat, an engine control system, a digitised cockpit, renewal of ageing structural parts and composite materials in the horizontal tail and part of the fuselage. The package was first shown at the 1997 Taipei Aerospace show with a full-size cockpit mock-up. When the US State Department failed to approve the export licence for the technical assistance agreement in time, AIDC ended the partnership and chose to develop its own programme: that was the start of Tiger 2000.

The aim was to keep the F-5E/F's air-to-air capability, strengthen its ground-attack role and turn it into a lead-in aircraft for the front-line fighters, using equipment as close as possible to that of the F-16A/B and F-CK-1A/B. The airframe and engines stayed those of the F-5E; the work focused on avionics and structure:

- a full structural overhaul to remove corrosion and extend service life; - the F-CK-1's GD-53 radar, with a smaller antenna to fit the F-5E's smaller nose (the GD-53 was derived from General Electric's AN/APG-67 developed for the F-20); - removal of the left-hand cannon to make room for the new avionics; - an F-16-compatible head-up display, colour multifunction displays and a digital cockpit; - H-764G laser inertial navigation integrated with GPS, plus a standard air data computer; - improved radar warning receiver and countermeasures dispensers; - hands-on throttle and stick controls and a MIL-STD-1553B databus to integrate all systems and leave room for growth.

AIDC took an F-5E in C configuration, serial 5308, from the air force's 5th Wing at Taoyuan. Years of use in Taiwan's hot, humid and salty climate had left it badly corroded, especially in the intakes, engine bays and skin; repairs ran from November 1998 to the end of April 1999. At the same time 437 modifications to structure, parts and wiring were made for the new avionics; parts manufacture was finished in June 2000 and ground testing in June 2001. In December 1999 AIDC said the air force was for now funding only the development aircraft, with no guarantee of a follow-on order, although it expected a contract to upgrade 40 aircraft, and that flight testing would last about two months after the first flight.

Tiger 2000 first flew on 24 July 2002, with test pilot Li Wen-cheng. The test programme was set at five flights. As well as the AIM-9P4 Sidewinder, the aircraft integrated the beyond-visual-range Tien Chien II (TC-2) missile on the centreline pylon, giving the F-5E an air-to-air capability it had never had. Some sources call it Tiger 2000/2001.

AIDC also hoped to sell the package abroad. In 1999 it named the Philippines, interested in up to 40 F-5s, Brazil, with about eight aircraft, and other unnamed South American countries as possible customers, and had signed a memorandum with Malaysia's Airod to offer the upgrade to the Royal Malaysian Air Force, which had about 16 F-5E/Fs: Airod would handle the structure and AIDC the avionics. None of these sales was ever made.

Although the prototype met its goals, the Taiwanese air force had just finished bringing its second-generation fighters (F-16, Mirage 2000 and IDF) into service, the defence budget was tight and the F-5E/F was due to retire in the 2010s. For the F-5s still left with the training unit at Taitung the upgrade was more than they needed, so it was not adopted. 5308 was retired after its test flights and since 2008 has been on display at AIDC's aerospace park in central Taiwan. The experience later helped AIDC with the mid-life upgrade of the F-CK-1A/B and the conversion of F-16s to the F-16V standard. Taiwan's last F-5Es retired in November 2023 without ever receiving this upgrade.