Editing Northrop F-5 (section)

===Upgrades===
The F-5E experienced numerous upgrades in its service life, with the most significant one being adopting a new [[planar array radar]], Emerson [[AN/APQ-159]] with a range of 20&nbsp;nmi to replace the original AN/APQ-153. Similar radar upgrades were also proposed for F-5F, with the derivative of AN/APQ-159, the AN/APQ-167, to replace the AN/APQ-157, but that was cancelled. The latest radar upgrade included the Emerson [[AN/APG-69]], which was the successor of AN/APQ-159, incorporating mapping capability. However, most nations chose not to upgrade for financial reasons, and the radar saw very little service in USAF aggressor squadrons and Swiss Air Force.<ref>{{cite web|title=F-5 Tiger II|url=http://www.touchdown-aviation.com/types/swiss-air-force/f-5-tiger-ii.php|website=Touchdown Aviation|access-date=29 January 2016|archive-url=https://web.archive.org/web/20160907134423/http://www.touchdown-aviation.com/types/swiss-air-force/f-5-tiger-ii.php|archive-date=7 September 2016|url-status=dead|df=dmy-all}}</ref>

Various F-5 versions remain in service with many nations. Having taken delivery of its first F-5 Tigers in 1979, [[Singapore]] operated approximately 49 modernized and re-designated F-5S (single-seat) and F-5T (two-seat) aircraft until the early 2010s when they were retired from service.<ref>{{Cite web|last=Waldron2018-02-04T04:02:00+00:00|first=Greg|title=SINGAPORE: RSAF chief discusses future capabilities|url=https://www.flightglobal.com/helicopters/singapore-rsaf-chief-discusses-future-capabilities/126941.article|access-date=2020-12-04|website=[[FlightGlobal]]|language=en}}</ref> Upgrades included new FIAR Grifo-F X-band radar from Galileo Avionica (similar in performance to the AN/APG-69), updated cockpits with multi-function displays, and compatibility with the [[AIM-120 AMRAAM]] and [[Rafael Advanced Defense Systems|Rafael]] [[Python (missile)|Python]] [[air-to-air missile]]s.<ref name="AFM275">Yeo, Mike. "Tigers over Lion City." ''[[AirForces Monthly]]'' ([[Key Publishing]]), Issue 275, March 2011, pp. 86–91. {{ISSN|0955-7091}}. Retrieved: 8 June 2011.</ref><ref name="FSRSAF">[http://www.mindef.gov.sg/imindef/mindef_websites/atozlistings/air_force/assets/aircraft/fighters.html "Press release: Assets: Fighter aircraft."] {{Webarchive|url=https://web.archive.org/web/20140202125847/http://www.mindef.gov.sg/imindef/mindef_websites/atozlistings/air_force/assets/aircraft/fighters.html |date=2 February 2014}} ''Ministry of Defence (Singapore)'', 24 April 2010. Retrieved: 8 June 2011.</ref><ref name="FGBRF5">[http://www.flightglobal.com/articles/2000/04/11/64402/brazil-favours-grifo-f-radar-for-f-5br-upgrade.html "Brazil favours Grifo F radar for F-5BR upgrade".] ''[[FlightGlobal]]'', 11 April 2000. Retrieved: 8 June 2011.</ref>

[[File:Northrop F-5E (modified) DARPA sonic tests 04.07R.jpg|thumb|NASA F-5E modified for DARPA sonic boom tests]]
One [[National Aeronautics and Space Administration]] (NASA) F-5E was given a modified fuselage shape for its employment in the [[Shaped Sonic Boom Demonstration]] program carried out by [[Defense Advanced Research Projects Agency]] (DARPA). It is preserved in the [[Valiant Air Command Warbird Museum]] at [[Titusville, Florida]].<ref>[http://www.vacwarbirds.org/AirplaneGallery/index.html "F5E-Modified."] {{webarchive|url=https://web.archive.org/web/20120212002603/http://www.vacwarbirds.org/AirplaneGallery/index.html |date=12 February 2012}} ''vacwarbirds.org.'' Retrieved: 24 April 2012.</ref>

The [[Royal Thai Air Force]] (RTAF) had their F-5s undergo an extensive upgrade program, resulting in the aircraft re-designated as F-5T Tigris. They are armed with Python III and IV missiles; and equipped with the Dash helmet-mounted cueing system.<ref>{{Cite web|url=https://www.ainonline.com/aviation-news/defense/2017-08-10/thailands-latest-f-5-upgrade-features-israeli-kit|title=Thailand's Latest F-5 Upgrade Features Israeli Kit|first=Chen|last=Chuanren|website=Aviation International News}}</ref>

Similar programs have been carried out in Chile and Brazil with the help of [[Elbit]]. The Chilean upgrade, called the F-5 Tiger III Plus, incorporated a new Elta [[EL/M-2032]] radar and other improvements. The Brazilian program, re-designated as F-5M, adds a new [[Grifo radar|Grifo-F]] radar along with several avionics and cockpit refurbishments, including the Dash helmet. The F-5M has been equipped with new weapon systems such as the [[Beyond Visual Range missile|Beyond Visual Range]] [[Derby (missile)#Derby|Derby]] missile, [[Python IV#Python-4|Python IV]] short-range air-to-air missile, [[SMKB]] "smart" bombs,<ref>"Bombas Guiada SMKB." ''Revista Asas''(Portuguese), Volume 61'', June 2011, p. 29. {{ISSN|1413-1218}}.''</ref> and several other weapons.<ref>[http://www.flightglobal.com/news/articles/denels-a-darter-makes-test-debut-323063/ "Denel's A-Darter makes test debut"] {{Webarchive|url=https://web.archive.org/web/20130521111653/http://www.flightglobal.com/news/articles/denels-a-darter-makes-test-debut-323063/ |date=21 May 2013}} ''Flight Global'', 26 February 2009. Retrieved: 28 January 2012.</ref><ref>[http://www.alide.com.br/noticias/fab39/index.htm "FAB comemora dia da Aviação de Caça!" (in Portuguese).] {{Webarchive|url=https://web.archive.org/web/20080919144151/http://www.alide.com.br/noticias/fab39/index.htm |date=19 September 2008}} ''alide.com.br.'' Retrieved: 28 January 2012.</ref><ref>[http://www.aereo.jor.br/2010/11/04/f-5em-com-missil-python-iv/ "F-5EM com míssil Python IV" (in Portuguese).] {{Webarchive|url=https://web.archive.org/web/20111225095509/http://www.aereo.jor.br/2010/11/04/f-5em-com-missil-python-iv/ |date=25 December 2011}} ''Poder Aéreo'', 4 November 2010. Retrieved: 28 January 2012.</ref><ref>[http://www.aereo.jor.br/2008/08/24/as-garras-afiadas-do-f-5em/ "As garras afiadas do F-5EM" (in Porguguse).] {{Webarchive|url=https://web.archive.org/web/20120216215335/http://www.aereo.jor.br/2008/08/24/as-garras-afiadas-do-f-5em/ |date=16 February 2012}} ''Poder Aéreo'', 24 August 2008. Retrieved: 28 January 2012.</ref>