Eurofighter Typhoon IPA6

IPA6 was the sixth Instrumented Production Aircraft of the Eurofighter Typhoon programme and the third supplied by the United Kingdom, after the two-seat IPA1 and the single-seat IPA5. Unlike the five earlier IPAs, which had been built as test aircraft from the outset, IPA6 began life as a production machine: airframe BS031, a British single-seat Tranche 1 aircraft that BAE Systems diverted from the delivery line and converted into a trials aircraft at its Warton site in Lancashire. It carries the Royal Air Force serial ZJ938, although throughout its career it has operated from Warton in industry hands. Its purpose was to bridge the first two production tranches: it retained a Tranche 1 structure but was fitted with the full Tranche 2 mission computer suite and avionics, together with new standards of hardware and software. In the programme's lists of development aircraft it appears exactly in those terms, as a converted series production aircraft dedicated to the Tranche 2 computer systems.

In early October 2007 IPA6 completed engine run tests at Warton. It was the first time the aircraft had worked as a complete system independently of ground support equipment, and the consortium presented it as the major milestone before clearance for first flight. The maiden flight came on 1 November 2007, with Mark Bowman, Eurofighter Typhoon test pilot at BAE Systems, at the controls; the aircraft was airborne for 54 minutes. Eurofighter GmbH announced the flight from Hallbergmoos as the first by a Typhoon carrying Tranche 2 avionics, and stated that the aircraft's first prominent task would be to achieve Type Acceptance for Block 8, the first capability standard of the second tranche, in April 2008. That work was shared with IPA7 (GS029), the German single-seater representing the full Tranche 2 build standard, which first flew at Manching on 16 January 2008 with Chris Worning at the controls. With IPA6 at Warton and IPA7 at Manching the programme had two aircraft for Block 8 qualification, and both were used for the flight testing of the new avionics required for the tranche's international certification. In parallel, the Italian IPA2 had concluded the first series of flights with Tranche 2 EJ200 engines at the end of November 2007.

The distinctive Tranche 2 capabilities centred on the new mission computers, which delivered the higher processing and memory capacity needed to integrate future weapons such as Meteor, Storm Shadow and Taurus; the remaining differences in build standard from Tranche 1 stemmed from changes in production technology or obsolescence. The Tranche 2 production contract had been signed on 14 December 2004 and committed 251 aircraft to the four partner nations (91 for the United Kingdom, 79 for Germany, including 15 originally contracted by Austria, 47 for Italy and 34 for Spain), with deliveries scheduled from summer 2008 until 2013. IPA6's work was therefore the precondition for those deliveries to begin, and industry described it as the aircraft that would clear the first Tranche 2 capability standard into service.

Once the Block 8 phase was over, IPA6 became a systems test bed. In June 2008 it flew a series of trials of the Praetorian defensive aids sub-system (DASS) together with the new avionics, as well as flights devoted to the Helmet Equipment Assembly (HEA) and the forward-looking infrared (FLIR) sensor, and it was designated the test bed for Service Release Package 5.1, due to be introduced to in-service aircraft. Since the end of 2012 it has been used for software validation. Italian sources also count it among the three British development aircraft (IPA1, IPA5 and IPA6) included in the Tranche 1 total delivered to the United Kingdom.

In the following decade IPA6 led the integration of the Brimstone air-to-surface missile under the Phase 3 Enhancement (P3E) package, part of Project Centurion, the programme intended to transfer Tornado capabilities to the Typhoon for the Royal Air Force by the end of 2018. Following ground testing and initial flight trials, BAE Systems completed at Warton a series of aero data gathering flights to check how the Brimstone load interacted with the flight control system software: around 40 sorties in all, flown with four AMRAAM, two ASRAAM, two Paveway IV bombs and two launchers each holding three Brimstone missiles, eight of them with pilots from the RAF's 41(R) Squadron within a Combined Testing Team. Steve Formoso, BAE Systems' chief test pilot, noted that the aircraft kept its manoeuvrability under that load. The trials culminated in nine live firings and nine jettison trials, supported by the UK Ministry of Defence, MBDA, QinetiQ, Eurofighter GmbH and the partner companies, with RAF evaluation planned for mid-2018. Initially configured to the Tranche 1 Block 5 standard and later raised to Block 8, the aircraft remains assigned to weapons trials for the British Typhoon.