Editing Hawker Siddeley Harrier (section)

===Tripartite evaluation===
[[File:Hawker Siddeley XV-6A Kestrel USAF.jpg|thumb|Hawker Siddeley XV-6A Kestrel in later [[USAF]] markings|alt=An aircraft landed on a runway]]

In 1961, the United Kingdom, the United States and [[West Germany]] jointly agreed to purchase nine aircraft developed from the P.1127, for the evaluation of the performance and potential of V/STOL aircraft. These aircraft were built by [[Hawker Siddeley]] and were [[British military aircraft designation systems|designated]] ''Kestrel FGA.1'' by the UK.<ref name= Jefford_39>Jefford 2006, p.&nbsp;39.</ref> The Kestrel was strictly an evaluation aircraft and to save money the Pegasus 5 engine was not fully developed as intended, only having {{convert|15000|lb(f)|kN|sigfig=2}} of thrust instead of the projected {{convert|18200|lb(f)|kN|sigfig=2}}.<ref name= Jefford_39/> The Tripartite Evaluation Squadron numbered ten pilots; four each from the UK and US and two from West Germany.<ref name= Jefford_39/> The Kestrel's first flight took place on 7 March 1964.<ref name= Jefford_41>Jefford 2006, p.&nbsp;41.</ref>

A total of 960 sorties had been made during the trials, including 1,366 takeoffs and landings, by the end of evaluations in November 1965.<ref>Spick 2000, p.&nbsp;362.</ref><ref name= Jefford_47>Jefford 2006, p.&nbsp;47.</ref> One aircraft was destroyed in an accident and six others were transferred to the United States, assigned the US designation ''XV-6A Kestrel'', and underwent further testing.<ref>Evans, A. "American Harrier – Part One." ''Model Aircraft Monthly'', Vol. 8, Issue 4, pp.&nbsp;36–39.</ref><ref>Mason, Kenneth J. and Charles R. Rosburg. [http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0855032 "USAF Evaluation of the Harrier GR Mk 1. – AD0855032".] {{Webarchive|url=https://web.archive.org/web/20170331001757/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0855032 |date=31 March 2017 }} ''Air Force Flight Test Center Edwards AFB'', June 1969.</ref><ref>Jenkins 1998, p.&nbsp;16. Retrieved 31 July 2011.</ref> The two remaining British-based Kestrels were assigned to further trials and experimentation at [[RAE Bedford]] with one being modified to use the uprated Pegasus 6 engine.<ref name="Mason 91 p419-0">Mason 1991, pp.&nbsp;419–420.</ref>