The Global Combat Aircraft Program (GCAP) is a multi-national next generation fighter initiative between the UK, Italy, and Japan. The aircraft is expected to be a large, twin-engine design featuring low observability (LO), an advanced power and thermal management system (PTMS), and networked multi-spectral sensors. GCAP may feature an unmanned component or individual countries might opt for their own country specific solution. Partner nations aim to begin fielding GCAP by 2035, with the aircraft expected to replace the Eurofighter Typhoons of Italy and the UK, as well as the Mitsubishi F-2s of Japan.

Program History

Key Highlights:

• As effectively middle powers, major European states are incentivized to form collaborative next generation fighter agreements to share development costs, achieve economies of scale, and secure export orders to ensure viability.
  • Historically, the UK & France have each served as distinct nexuses for joint European fighter programs, with each having unique preferences both operationally and industrially with respect to the U.S. and NATO.
• Japan’s industrial base has been shaped by decades of low defense spending and a ban on arms exports – leading to both high cost, low volume domestic programs supported by a small but highly skilled workforce.
  • Japanese industry has developed competitive advantages in avionics, missiles, and ceramic matrix composites.
• Development of the UK’s Future Air Combat System (FCAS) & Tempest fighter initiative was arguably not financially viable without the involvement of Japan. The F-X program was similarly anticipated to face “death spiral” pressures during the production phase with a procurement objective of only 90 aircraft. These challenges contributed to the merger of both programs.

United Kingdom & Italy: FCAS & Tempest

Pre-History: Eurofighter, Rafale & Familiar Patterns (1978-1985)

The genesis of two distinct consortiums amongst European nations during the 1980s and into the 1990s, shares many similarities to the continent’s current fighter projects in terms of the influence of distinct national priorities, comparative industry specialties, as well as diplomatic and military friction between allies.

The Eurofighter and Rafale programs originate from a 1978 study between the UK, Germany and France on a common future fighter aircraft. Germany and the UK maintained similar requirements as F-4 Phantom operators, requiring a fighter optimized for air superiority and interception. The French desired a multi-role aircraft – with an emphasis on air-to-surface first, to replace its Mirage-2000s and Jaguar fleets. The joint program was shelved in 1981 and the Panavia consortium partners involved in the Tornado program (BAE, Aeritalia and Messerschmitt-Boelkow-Blohm) launched the European Fighter Aircraft (EFA) program and the associated Experimental Aircraft Program (EAP) demonstrator in October 1982. The French announced their own Avion de Combat experimental (ACX) demonstrator that December, which would build upon earlier French investments in the Snecma M88 (now Safran) engine, airframe and avionics technologies. By the end of 1983, the chiefs of staff of the UK, Germany, Italy, Spain and France were again discussing a common EFA configuration, but irreconcilable differences emerged between the UK and France for design leadership between 1983-1985.

The foundational element defining French defense industrial policy in the Fifth Republic has been to maintain a self-sufficient industrial base in all aspects – including aircraft design such as airframe, avionics, engine technologies. The French increasingly viewed cooperation with so many partners as detrimental to not only preserving but also expanding its industrial capabilities. Germany and the UK in particular, favored developing the Rolls-Royce & MTU RB199 engine rather than the M88, which would effectively end France’s military turbofan industrial base. The UK and France each sought to entice German cooperation in 1984 with the German Foreign Minister supporting partnership with France and both the Defense Minister and Chief of Staff of the Luftwaffe strongly favoring a partnership with the UK. Ultimately, Bavaria’s Christian Social Union (CSU) party applied significant pressure to partner with the UK in order to preserve MTU’s engine expertise. Furthermore, Germany had already committed to codevelop a next generation attack helicopter with France – in what eventually become the Airbus Tiger. With German support for the UK, Italy soon followed. Spain briefly maintained cooperation with France on ACX, but by the end of 1985 France was left without any international partners. The four remaining nations would proceed to develop the Eurofighter Typhoon and France would develop the Rafale on its own.

UK Experience in LO Programs 1986-2005

The UK has explored low observables since at least the 1980s when the RAF considered acquiring the F-117 between 1986-1987. RAF pilots were briefed into the program and participated in flight tests in Nevada. The RAF briefly evaluated the F-117 for a second time in the early 1990s. Lockheed proposed a highly modified F-117 (which is inconsistently referred to as the F-117B or F-117C in secondary sources). The design included a nose mounted radar, enlarged weapon bay and new larger wings. BAE was offered component work and the aircraft would have used EJ200 turbofans, originally developed for the Typhoon. The UK was also involved in the F-35 percussor programs of the 1980s, which dealt with LO, including Advanced Short Take-Off/Vertical Landing (ASTOVL).

After Operation Desert Storm in 1991, the UK explored acquiring a LO replacement for Tornado as part of the Future Offensive Aircraft (FOAS) program; which established UK LO industry expertise. Between 1994-1999, BAE matured its Replica design study hich concluded in a series of radar pole tests. The Replica planform included a forward chine, lambda wings and V-tails – design details that were subsequently incorporated into BAE System’s Tempest concept. The Replica model was assembled at BAE Systems Warton from large carbon fiber composite skins manufactured by BAE Systems Samlesbury. FOAS was canceled in 2005 as the UK shifted to consider UAVs instead.

UCAV Focus & UK-French Cooperation 2005-2017

In 2005, the UK released its Defence Technology Strategy (DTS) and Defence Industry Strategy (DIS) reports, which established future industrial base priorities. The DTS eschewed the development of a new follow-on fighter, stating:

“The anticipated multi-decade operation of the Joint Strike Fighter and Typhoon has removed the requirement for the UK to design and build a future generation of manned fast jet aircraft for the foreseeable future… The DIS identifies the UAV as an emerging system in aerospace. Although there are powerful drivers for the employment of unmanned systems (see subsection on UAVs), the development and employment of advanced combat capable UAVs clearly provides significant technical challenges. It also provides an opportunity for technological innovation to challenge the traditional economics of development, manufacture and employment of air systems.”

At the time, the Typhoon had recently entered RAF service (2003) and production was expected to continue well into the next decade while development of the F-35 was ongoing. Instead, the DIS argued that the UK needed to cultivate national design expertise with respect to unmanned systems and low observables. By launching an unmanned combat aerial vehicle (UCAV) technology demonstrator, the MoD would also be able to better assess the role of unmanned systems within its future force structure. The UK subsequently launched the Strategic Unmanned Air Vehicle (Experimental) (SUAVE) program and the associated Taranis Technology Demonstrator. In December 2006,BAE Systems was awarded £124 million to develop Taranis, with support from QinetiQ, Rolls-Royce and Smiths Aerospace. Fabrication of Taranis began in 2007 and flight testing began in 2013. Around this time, France’s Dassault was working on its own nEUROn UCAV demonstrator, which first flew in 2012.

Generally recognized as the two foremost European aerospace authorities, the UK and France had hoped to at least partially cooperate on their next generation combat aircraft prior to Brexit in 2016. In November 2010, the countries signed the Lancaster House treaties, which promoted defense cooperation on a range of issues including aircraft carriers, communication systems and UAVs. In 2014, both nations jointly awarded £120/€150 million to BAE Systems, Rolls-Royce, Finmeccanica as well as Dassault, Thales and Safran, as part of the Future Combat Air System Demonstration Program Preparation Phase (FCAS DPPP). In February 2016, UK Prime Minister (PM) David Cameron announced that both nations would invest £1.54 billion ($2 billion) to fund a next generation UCAV prototype with flight testing by 2025 and an initial operational capability (IOC) by 2030. However, with the referendum on Brexit in June 2016 and 0David Cameron’s subsequent resignation as PM in July, further Anglo-French cooperation stalled. Therefore, in lieu of these events, France began to more seriously explore defense cooperation with Germany.

Upon taking office in May 2017, French President Emmanuel Macron sought to establish greater strategic autonomy for Europe vis-à-vis the U.S. With Brexit and the decline of transatlantic relations following the 2016 presidential election of Donald Trump, France was left in a unique position within the European Union (EU) as the bloc’s sole nuclear power, as well as a key aerospace industry leader and a major security provider. President Macron perceived a Franco-German alignment as a core pillar of Europe’s future autonomy. In July 2017, France and Germany agreed to jointly develop a next generation fighter and FCAS DPPP, which had stalled by 2018, was effectively canceled by 2019.

Manned Fighter Focus, Search for Partners, Combat Air Strategy 2015-2018 

By the time FCAS DPPP was facing political headwinds, the landscape of the UK’s industrial base and fiscal environment had completely changed relative to the 2005 DIS/DTS. BAE System’s Warton production line would soon conclude the RAF’s order for 160 Typhoons in 2019. The Eurofighter consortium had limited export success for the type beyond Europe and the Gulf. Similarly, production of BAE’s Hawk advanced jet trainer would soon end after 40 years. UK industry still maintained a 15% stake in the F-35 program, but lower fiscal outlays and rising program costs cast doubt on the UK’s original procurement goal of 138 aircraft. The MoD’s budget fell from 2.5% to 2% of GDP from 2010-2015 and did not increase significantly until the 2017/2018 period. Crucially, with the end of Taranis and FCAS DPPP, UK industry had limited opportunities for further research and development work. The pressures from domestic industry to cultivate human capital and support the local economy created the foundational imperative for a new manned fighter program.

As part of the 2015 SDR, the UK quietly began its Future Air Combat System Technology Initiative (FCAS TI) – an effort to mature a group of capabilities to replace Typhoon and inform a 2025 decision on further development. One of the earlier visible signs of the UK’s pivot towards a manned fighter came in March 2017 with the formation of a joint Japan-UK fighter working group. By February 2018, UK Defence Minister Gavin Williamson announced that the MoD would produce a new Combat Air Strategy, which was subsequently unveiled that July. Williamson formally announced the Tempest project to develop a new manned fighter at the 2018 Farnborough air show stating, “early decisions on how to acquire the capability will be confirmed by the end of 2020, before final investment decisions are made by 2025.” At the time, the MoD planned to spend at least £2 billion ($2.65 billion) through to 2025, to support technology maturation and risk reduction activities prior to full-scale development. Under the proposed schedule, Tempest would achieve initial operational capability (IOC) by 2035. At the time of the announcement Team Tempest included BAE Systems, MBDA, Leonardo UK and Rolls-Royce (RR).

Search for International Partners 2018-2021

For the UK, international collaboration was imperative. Each generation of combat aircraft has proven to be more expensive and technically demanding than the last. The UK financed 33% of the Eurofighter’s development costs at $11.8 billion in inflation adjusted 2022 US dollars. International participation would further reduce procurement costs through economies of scale. After the Farnborough announcement, the UK government launched diplomatic outreach efforts to Italy, Sweden and Japan.

For decades, Italy has viewed the UK as its primary European defense industrial cooperation partner. The two nations forged a comprehensive relationship during the Tornado program which was solidified further by the Typhoon project. At that time, Italy’s Typhoon final assembly line was expected to close in the early 2020s absent additional export orders. After the July 2018 Farnborough air show, the UK and Italy launched a joint fighter feasibility study examining common requirements. That September, Italian Defense Undersecretary Angelo Tofalo remarked that Italy “should join Tempest immediately in order to be at the forefront of cooperation with the UK.” Italy formally joined the UK FCAS program on Sept. 11, 2019 when Secretary General of Defense – Lt. Gen. Nicolò Falsaperna, signed a statement of intent. Multiple Italian government and industry officials have occasionally voiced a preference to merge Tempest with SCAF, but this possibility remains unlikely.

Saab has a distinguished history in producing jet fighters since the 1940s and Sweden’s government has ensured its industrial base persists with each new generation of indigenous combat aircraft. Sweden has often partnered with the UK on subcomponent work. BAE Systems had a role in marketing the Gripen in the early years of the program and UK components represented 30-35% of the total value of each Saab JAS 39 Gripen produced. UK-Swedish FCAS discussions began in 2018 and culminated in a July 2019 memorandum of understanding (MoU) to explore future fighter technologies. In July 2020, Saab announced it would establish a “FCAS center of excellence” worth £50 million ($63 million) in Sweden. Unlike Italy, Sweden has not committed to the Tempest manned fighter. Sweden is instead interested in collaborating on the broader set of technologies within the FCAS SoS. In February 2021, Saab’s CEO Michael Johansson said that that Sweden’s participation in FCAS would bring additional capabilities to its GlobalEye and Gripen E platforms.

Japan launched its F-2 fighter replacement program in 2016 and quickly sought out opportunities to collaborate with the UK. Both countries foresaw the need to lower costs and leverage unique expertise between countries. A vocal contingent within the Japanese MoD and Parliament believed partnering with the UK would bring greater opportunity for local industry and secure more robust intellectual property (IP) rights. This group believed that any partnership with the U.S. would be marred by “black boxes;” components that could not be fully explained to Japan over security or IP concerns. In contrast, Japan Air Self Defense Force (JASDF) officials appeared to be more supportive of an American partnership.

In response, the U.S. government showed a renewed willingness to address intellectual property issues and Japan subsequently established U.S. fighter working group in September 2019. The Japanese MoD’s appraisal of Tempest also soured throughout the latter half of 2019 as it became clear that the UK would seek to retain leadership of any joint fighter program at the cost of Japanese industry. By March of 2020, the Japanese government decided future cooperation with the UK would be limited to a subsystem level – the most significant being joint engine components and technologies. However, this would ultimately change in 2022. Refer to the Japan F-X section for additional details.

In December 2020, the UK, Italy, and Sweden signed an MoU to codify their FCAS relationship.

2021 Integrated Review & Defence Command Paper

In March 2021, the UK released its Integrated Review and associated Defence Command Paper (DCP). The document affirmed the 2018 combat air strategy, stating the UK would invest over £2 billion in FCAS through 2024:

“Our investment in the Future Combat Air System (FCAS) programme represents a paradigm shift in the UK’s combat air industrial sector to achieve the pace, affordability and operational capability we need to meet our requirements. This approach will deliver capabilities twice as fast, at a lower cost, designed and delivered in a fully digital enterprise. Exploiting model-based design, systems engineering and embedding the latest agile design principles to deliver faster. FCAS has already created over 1,800 new STEM jobs in over 300 companies nationwide, sustaining and supporting over 18,000 existing highly skilled jobs in the sector, as well as tens of thousands more in the wider supply chains across the UK.”

Left explicitly unstated was how the UK would fund FCAS. The IR was accompanied by a multiyear funding agreement to give the MOD an additional £16.5 billion ($22 billion), or approximately £4 billion ($5.3 billion) extra per year. However, the DCP also announced a number of high-profile RAF fleet retirements including the Typhoon Tranche 1, C-130J transport, Hawk T1 trainer and E-3D Sentry ISTAR fleets. Most significantly, the DCP cut F-35B procurement from 138 to 70-80 airframes. It appears that the RAF is paying for FCAS by cutting these legacy fleets and trimming F-35 procurement.

For further developments and analysis on budgeting, production and schedule refer to the Production & Delivery history section of the profile.

Japan: F-X

The F-X’s history can loosely be categorized into three eras: the development of the preceding F-2, early conceptual studies and technology demonstration efforts and contemporary efforts to launch the F-X program.

Pre-History: FS-X (F-2) Program (1982-2011)

Even before production of the F-2 ended in 2011, Japan had begun efforts to develop a successor. Perceived deficiencies in the F-2 program shaped the F-X’s ambitions and requirements, with the MoD essentially seeking to avoid a repeat of the F-2. In 1982, the Japanese Government began the Fighter Support Experimental (FS-X) program to replace the indigenously designed Mitsubishi Heavy Industries (MHI) F-1 fighter. The U.S. lobbied Japan to develop the FS-X from an existing U.S. design in 1985. This U.S. effort sough to promote greater U.S.-Japan interoperability and mitigate the possibility of an independent Japanese national security policy. A key piece of the U.S.’ leverage was its engine technology which Japan would have required even under an indigenous development program.

Japan eventually acceded to U.S. demands and selected the F-16C Block 40/42 as the basis of further FS-X development in October 1987. The program was quickly hampered by American reticence to transfer key technologies and disagreement over the scope of Japanese industry participation. Lockheed Martin was awarded $75 million ($123 million in 2020 dollars) to support the development of the F-2 in October 1996. The company would be responsible for 40% of the program’s workshare by value including the avionics support equipment, the data entry electronic units and the stores management system.

In the end, the F-2 program produced a fighter featuring novel technologies such as the first fighter mounted active electronically scanned array (AESA) radar, but at an unacceptable cost and with no roadmap to keep the type technologically relevant. The F-2 had a flyway cost of $122.6 million in adjusted 2020 dollars and only 98 airframes (including four test articles) were produced between 1996 and 2011.

Japanese sources maintain that the F-2’s intellectual property agreements with the U.S. severely constrained its ability to upgrade the type. In many respects, current configuration F-2s remain less capable than contemporary F-16 Block 70s such as in stores compatibility, avionics, data links, and self-protection equipment. Some Japanese sources have derided the FS-X’ limited opportunities for Japanese industry and have expressed frustration against the U.S.’ technology and export policies. These grievances later influenced Japan’s decision to reject LM’s F-22/F-35 hybrid proposal.

Genesis of F-X (2005-2018)

According to Lt. Gen. (Ret.) Takayoshi Yamazaki, the genesis of F-X did not begin with a statement of need or requirements process from the MoD or JASDF. Rather, the program began from a 2007 industry assessment, which concluded that Japanese companies were withdrawing from the aerospace market. A similar study published in 2009 by the MoD (戦闘機の生産技術基盤の在り方に関する懇談会 中間取りまとめ) stated that the number of aerospace engineers in Japan was expected to decline by 70% after F-2 production ended in 2011. To ameliorate further attrition of the industrial base, the MoD’s Technical Research and Development Institute (TRDI) and MHI began work on the Advanced Technology Demonstrator – X (ATD-X) “Shinshin” (Spirt of the Heart) in 2007. At the time, the MoD remarked, “A quick start [of the program] is essential to sustain the domestic military technological base and to obtain bargaining power.” The comment followed an unsuccessful campaign to import the Lockheed Martin F-22A Raptor.

The resulting ATD-X design has an empty weight of 29,000 lb. and features caret inlets, canted vertical stabilizers and planform alignment to reduce its radar cross-section (RCS). The design is powered by a pair of IHI XF5-1 turbofans producing 11,000 lbf. of thrust and which are fitted with thrust vectoring paddles attached at the end of each nozzle. The ATD-X airframe underwent static fatigue life testing in 2013 and was rolled out a year later. It first flew in April 2016 following a year-long delay prompted by unspecified issues with the aircraft’s low observable (LO) features. As of November 2017, the ATD-X had flown 34 of the planned 50 test fights and was scheduled to be withdrawn from service in March 2018.

According to program manager Hirofumi Doi, the ATD-X program gave F-2 engineers the opportunity to pass skills to the next generation of Japanese aerospace engineers. The Society of Japanese Engineers found that just 20% of the 270 engineers across the main Japanese primes involved in the F-2 program remained in the workforce as of November 2017. Another critical element of the program was the development of associated test infrastructure, which would later be needed in a full scale developmental program such as RCS measurement and ranging equipment. A total of $664 million was spent on the advanced technology demonstrator between 2009 and 2017.

Trade Studies & Concept of Operations

While Japanese industry gained experience in basic LO design and shaping under ATD-X, the MoD began the “i3” program. First disclosed in 2010, the i3 sought to develop technologies not covered under the ATD-X program such as slim engines capable of supercruise, electroconductive canopy materials, metamaterials for controlling radio waves passing through the radome, data integration for counter-stealth applications and cooperative sensor and weapons employment.

TRDI examined scenarios in which Japan would have to combat a larger adversary in a close or distant geographical context. Results from these studies indicated the need for high survivability via LO, deep magazine capability for air-to-air missiles (AAMs) and cooperative engagement capability. Speed was shown to not greatly improve mission performance. More important to aircraft survivability is the range of angles at which the aircraft can paint targets with its radar and guide missiles toward them. TRDI found that increasing a fighter’s radar sweep from about 140 deg. (that is, 70 deg. either side of the centerline) to about 220 deg. gave the pilot more time in which to fire missiles and reduced the enemy’s opportunity by around 40%. If the range of available guidance command directions is increased from about 200 deg. to 360 deg., the time available for the pilot to fire is almost doubled and the enemy’s is almost halved.

TRDI (likely with support from MHI) produced aircraft design concepts in 2011, 2012, 2013 and 2014 which were successively designated 23DMU, 24DMU, 25DMU and 26DMU. (Note that the number in each designation corresponds to the regnal year of then Emperor Akihito. DMU stands for digital mock-up.)

The series of designs shows a progressively stronger emphasis on LO design illustrated by the flattening of the aircraft, moving the engines outboard and changing from straight intakes with radar blockers to S-shaped ducts. Earlier emphasis on maneuverability and speed gave way to focus on endurance, loiter time and weapons load. A detailed explanation of each concept design follows.

• 23DMU – This concept shared the planform of the ATD-X. Its overall design prioritized maneuverability and incorporated carriage of four BVR air-to-air missiles (AAMs) as well as a pair of within-visual-range (WVR) weapons. TRDI found the 23DMU’s deep fuselage contained significant radar-reflecting side area.
• 24DMU – The next design was a refinement of the 23DMU intended to reduce side reflecting area by flattening the aircraft. The engines were moved outboard and fed with straighter ducts, relying on blockers to reduce the RCS. The BVR AAMs were carried in tandem pairs. A V-tail combines both rudder and elevator functions as on the Northrop YF-23. Simulations with the new design found a pilot flying a 24DMU instead of a 23DMU would be able to fire about 10% more missiles and the enemy about a third fewer. The time available for taking shots was shorter for both, but the enemy’s firing interval suffered more.
• 25DMU – This design has a greater emphasis on LO when compared to the preceding concepts. In place of the straight, blocked inlets, 25DMU has S-ducted intakes with inboard engines to create a broad space for side-by-side stowage of six BVR AAMs under the ducts, which twist upwards and inwards. The four tail surfaces reappeared but the fins remained highly canted and were kept shorter than those of the 23DMU. Wingspan and aspect ratio increased by almost 20% compared to the 24DMU. These wing changes were expected to increase range through an improved lift to drag ratio and greater fuel volume. TRDI confirmed range increased with the 25DMU, though it gave no figures. Speed and acceleration likely suffered, especially since 25DMU appears at least 10% larger than its predecessors. All of TRDI’s published designs show a modest 40-deg leading-edge sweep of the main plane, suggesting none were designed to supercruise, but rather to enhance range and loitering time.
• 26DMU – The final design preserves the concept of long-endurance and moderate flight performance. 26DMU represents the final attempt by the ministry’s engineers to evaluate the trade-offs in the performance and acquisition of the new fighter. Implying the formation of more stable program requirements or key performance parameters.

F-X technology maturation funding from 2010-2020, by category.

Following ATD-X and the DMU series, the MoD’s Acquisition, Technology and Logistics Agency (ATLA) proceeded to fund technology maturation and risk reduction efforts totaling ¥227.7 billion yen ($2.19 billion) by the end of 2020. Featured above is a translated MoD graphic which describes the conceptual design work, airframe integration technologies (such as internal weapon bays), engine technology and avionics. See the features section for additional details on each category.

F-X Competition: 2016 – December 2020

Following DMU studies, work on F-X work greatly accelerated around 2016. The MoD evaluated three development paths:

(1) importing an existing design,

(2) modifying an existing design

(3) creation of a new fighter.

In June, the MoD released its first RFI seeking an existing aircraft that could be modified to meet Japan’s F-X requirements. Primes responded with the following modified designs: Lockheed Martin offered its F-35 (according to Nikkei), Boeing the F-15 and BAE Systems offered the Eurofighter Typhoon. Saab also responded to the RFI according to Swedish Ambassador Magnus Robach. That October, Lockheed Martin’s CEO Marillyn Hewson confirmed that it had partnered with MHI to respond to the MoD’s latest RFI.

In March 2017, the UK and Japan formed a fighter study group – two years prior to the formation of an equivalent body with the U.S. This marked a period from 2017 into mid-2019 in which Japan seriously considered partnering with the UK over the U.S. Some believed partnering with the UK’s Tempest program would bring greater opportunity for local industry and secure greater intellectual property rights with respect to upgradability and exports. Several Japanese sources evinced concern that any partnership with the U.S. would be marred by “black boxes;” components that could not be fully explained to Japan over security or intellectual property concern. In contrast, development of the Joint New Air-to-Air Missile (JNAAM) between the UK and Japan (which began in 2014) was seen as a model for future cooperation.

Concurrent to UK efforts to pursue cooperative development, Lockheed Martin pursued modification of an existing design – utilizing an F-22 airframe with F-35 avionics. According to Nikkei, the proposal included:

• At least 50% workshare for Japanese firms.
• Transfer of some engine development and production to Japan, with the country responsible for up to 60% if IHI’s XF9-1 were used.
• MHI would be responsible for designing and producing the wings (as on the F-2).
• Integration of the F-35’s radar and avionics with support from Mitsubishi.
• Incorporation of LO technologies from the F-35 to reduce maintenance burden compared to earlier LO features on aircraft like the F-117, F-22, and B-2.
• Design changes giving the hybrid a range of 1,188 nm (2,200 km).
• Sending F-22s to Japan to hasten developmental work (it is unclear how this would materialize due to the frozen production line and the export ban – only limited number of inactive F-22 airframes exist such as ground maintenance articles).
• Integration of Japanese weapons (presumably JNAAM and the ASM-3).
• A fly-away cost estimate by Lockheed Martin of ¥24 billion yen ($232.6 million) for a production run of 70 fighters or ¥21 billion ($204 million) for 140 units.
  • Air dominance capability.

Some reports suggest that this hybrid design may have similarities to the proposed FB-22. It is worth noting that LM originally offered several different FB-22 iterations to nthe USAF which to varying degrees fit F-X program requirements (including F/A-22 Spiral 5 and FB-22-1 through FB-22-4). Relevant FB-22 features include side array AESAs, improved LO, an expanded internal weapons bay and significantly greater range (1,477 nm combat radius with 100 nm dash at Mach 1.5). However, the FB-22 was limited to 6g of maneuverability performance and could not meet the Mach 2.0 F-X speed requirement. When combined with F-35 avionics and manufacturing techniques – such as LM’s laser radar alignment system and other metrology tools, the resulting fighter may have met or exceeded many of the F-X’s stated performance requirements. However, the principal measure of merit for the MoD at that time was industrial workshare, human capital development and the freedom to repair and upgrade the F-X.

While not directly involved with the acquisition process, lawmakers pressured the Shinzo Abe Administration for years to prioritize indigenous development – some explicitly advocating against the LM proposal. A dozen members of the LDP Defense Parliamentary League drafted a report entitled “Study Group on Japan’s Industrial Base and Future Fighter Aircraft” (日本の産業基盤と将来戦闘機を考える研究会) in 2018. The chairman of the group, Seishiro Eto (衛藤征士郎), met with Prime Minister Abe to discuss the F-X on June 20th, 2018. When pressed to commit to a domestic program, PM Abe remarked that the government will carefully consider tradeoffs with respect to acquisition, development and sustainment. That same month, LM responded to the F-X RFI with its hybrid proposal. In November 2018, the LDP Parliamentary League met with Defense Minister Takeshi Iwaya (岩屋毅) who briefed lawmakers on the F-X’s key metrics of evaluation, which were:

• Upgradability and growth potential to incorporate emerging technologies.
• Freedom for Japan to modify and repair the type.
• Domestic industrial base participation.
• Affordability.

Fighter working group meeting in November 2018. The group’s aim was to establish a framework for F-X development, focusing on industrial policy. Representative Masahisa Sato (佐藤 正久) is a prominent voice on Japanese national security issues and has served as both Deputy Defense Minister and Deputy Foreign Minister. He now serves as Secretary General to the LDP Defense Parliamentary League (自民党国防議員連盟). Other prominent members of the group include former defense ministers Gen Nakatani (中谷 元) and Yasukazu Hamada (浜田 靖一).

Credit: Masahisa Sato

Many viewed the hybrid proposal as a repeat of the F-2 program; a modification of an existing design and as such carrying a limited workshare of approximately 50%. Nikkei reported the aircraft’s airframe and engines would be built in the U.S. with a gradual transition for Japanese industry. Lockheed and GE had a similar phased arrangement with the F-2 program. LM would ultimately produce 80% of left-handed wing boxes as well as all leading-edge flaps, upper skins for left-handed wings and the aft fuselages – representing 40% of the value of the program. Japanese sources were also quick to voice their concerns over “black boxes” and the ability to repair and upgrade LM’s hybrid proposal. In the context of these concerns and the growing prospect of a Japan-UK partnership, LM offered to share the source code for the F-35 as part of F-X in March 2019. In response to Parliamentary questioning by Representative Seiji Maehara (前原誠司) in June 2019, ATLA Commissioner Nobuaki Miyama (深山延暁) indicated that derivative designs were not worth consideration if Japan could not obtain the source code.

The renewed willingness of the U.S. to address intellectual property issues as well as the realization by Japanese officials that the UK would seek to retain leadership of any joint fighter program, likely improved the U.S. position from the latter half of 2019 – culminating in the formation of a U.S.-Japan fighter working group in September. By early November, Defense Minister Taro Kono downplayed any potential partnership with Europe given the need to maintain commonality with the U.S. In this context, Air Commodore Daniel Storr (head of combat aircraft acquisition for the UK MoD) made three visits to Japan in the latter half of 2019. At the DSEI Japan conference held between Nov.18-20, Storr stated Japan could pick and choose elements of Tempest to include weapons, propulsion, airframe, powerplant and other subsystems. Storr suggested Japan would be able to maintain leadership of F-X and save money under this framework.

The end of 2019 also marked a solidification of program requirements. The Chief of Staff of the JASDF sent F-X requirements to the Commissioner of the ATLA in September. These requirements generally adhered to earlier studies emphasizing LO, range, sensors and deep magazine capacity. According to JASDF Lt. Gen. (Ret.) Takayoshi Yamazaki, the following requirements were specified in the September 2019 request:

• Core system of next generation combat system in multidomain operations
• In flight datalink capable of networking with ground and maritime systems
• Superior stealth capability
• Integrated sensor system with superior detection performance
• EW capability to maintain operations in a contested environment
• High missile capacity
• Interoperability with U.S. forces
• Extensive combat radius

With the F-X requirements solidified, the MoD became skeptical that derivative designs could meet requirements. On Nov. 26th, 2019, the 防衛省政策評価に関する有識者会議 or “Expert Committee on Policy Evaluation of the Ministry of Defense” discussed F-X development paths. The group concluded a new design led by Japanese industry, in partnership with a foreign prime, was the only means to ensure the integration of rapidly evolving, next generation technologies. The Japanese publication Jwing reported that the LM and Boeing derivative proposals were removed from consideration by December as they did not meet MoD requirements (BAE’s Typhoon had already been withdrawn from consideration). In March of 2020, Reuters also reported Japan had rejected derivative designs and opted to develop a new aircraft with international assistance. Following that decision, Representative Takashi Uto (宇都隆史) stated that neither the MoD nor the political leadership saw the F-22/F-35 hybrid as a viable proposal in April 2020. He emphasized Japan had to take the initiative during the development process to ensure freedom to repair and overhaul. Representative Kenji Wakamiya (若宮健嗣) was similarly incredulous of the hybrid proposal, stating the design would be obsolete within 15 years.

Caption: Major Gen. Masahito Monma (門間政仁) pictured above was selected to lead the F-X program office in April 2020. At the time of his promotion to Major Gen. in 2017, he was the youngest serving JASDF officer to attain that rank, having begun his career flying the F-15. Prior assignments include commanding the 204th Squadron (based in Okinawa), serving on the Joint Staff, Air Staff, and commanding both the 6th Air Wing and Komatsu Air Base. A team of approximately 30 people are expected to work within the office including technical experts and JASDF personnel.

Image Credit: JASDF

In March, Sankei reported that Japan had selected the U.S. as its principal developmental partner. Cooperation with the UK would continue at the subsystem level. By May 2020, the U.S.-Japan governmental working group had concluded, and a new industry group was formed. This group consisted of Lockheed Martin, Boeing, Northrop Grumman and about 10 Japanese companies including MHI, IHI and Toshiba. Separate discussions were held with four UK-based companies. The MoD briefed the lawmakers on July 15th on the status of discussions with the U.S. and UK and delivered the report, “The development status of the next fighter” (次期戦闘機開発状況について). The document outlined future MoD plans and systems within F-X as well as the status of discussions with the U.S. and the UK. Representative Masahisa Sato published the following schedule from that report:

• October 2020, choose an airframe contractor
• 2020, choose foreign partners
• 2024, begin building prototypes
• 2027, complete basic design of main components
• 2028, first flight
• 2031, begin volume production
• 2035, first delivery

The MoD considered the following contracting strategies for F-X: (1) a single prime contractor, (2) multiple prime contractors (like the F-2 and P-1), (3) creating a company specifically to develop the fighter (4) or forming a joint venture. The increasing complexity of LO and systems integration work ultimately convinced the MoD to pursue a single prime contractor model in March 2020.

In August 2020, Defense Minister Taro Kono (河野太郎) announced foreign primes had until the 31st to submit applications to participate in F-X development. Representatives from Rolls Royce and BAE Systems met with LDP lawmakers. On Aug. 25, the MoD released a request for information (RFI). The document stated that providers must have technology readiness seven (TRL7) or higher solutions to the following requirements: (1) technology for designing fixed wing aircraft, including LO UAVs, (2) systems integration technology with respect to aircraft mounted missiles including radar, IR sensors, ESM and data links. TRL7 denotes a stage of development where a prototype system is available and in testing within an operationally representative environment. The following month, the Defense Minister announced seven foreign companies had expressed interest in the F-X. He refused to identify the companies, but secondary sources believe the following companies responded: Lockheed Martin, Boeing, Northrop Grumman, BAE Systems, Airbus, Saab, and Rolls Royce. Note, September also marked the beginning of Yoshihide Suga’s (菅義偉) term as PM. Nobuo Kishi (岸信夫) was appointed to lead the MoD and Taro Kono was reassigned to lead the Ministry of Administrative & Regulatory Reform.

In early October, Japanese Media announced the MoD will start full-scale development of a UAV which will accompany the F-X. Flight testing is expected to begin within six years (see the UAV section under features section for additional information). On Oct. 30, Defense Minister Nobuo Kishi announced that MHI had been awarded a contract to develop Japan’s next generation fighter. Under this contracting strategy, MHI is responsible for coordinating industry and is expected to award contracts for engine and avionics development according to Nikkei. By November, three foreign primes remained under consideration for MHI’s principal co-developmental partner: Lockheed Martin, Boeing and BAE Systems. Northrop Grumman partnered with Lockheed Martin, likely focusing on mission systems or subcomponent assembly. In his new capacity, Taro Kono held a review of the F-X program. This followed reporting that he had pushed for a lower cost UCAV to replace the F-2 when he was Defense Minister.

On Dec. 11, 2020, Nikkei reported LM had won source selection. The paper cited LM’s incumbency in LO and system integration as deciding factors in addition to the company’s significant existing presence in Japan. The MoD formally announced the source selection in a December 18 press release. According to the release, LM will provide Japan with expertise in mission and system integration and “mobility and stealth” (運動性能とステルス性の両立). The release also stated that MHI will hold discussions with LM and conclude a contract. LM will obtain export licenses and coordinate with the U.S. to ensure interoperability. In response to the announcement, Representative Masahisa Sato stated that if LM does not disclose enough information or if its cost estimate is too high, another company can be selected.

Growing UK-Japan Collaboration

Among the earliest public signs that Japan would join GCAP was the Dec. 22^nd, 2021, announcement that the UK and Japan sought to explore common engine technologies, and possibly components, to share across the Tempest and MHI F-X programs. The UK would contribute an initial investment of £30 million with a further £230 million for a full-scale demonstrator. The project was slated to run through the mid-2020s. Two days later on Dec. 24, 2021, Japan’s ATLA issued an RFI for low bypass ratio engines to international primes. The document specified “technical information required for integration of power and thermal management systems, stealth and flight control”.

The announcement comes after nearly two years of discussions. In November 2020, Rolls Royce (RR) director of future programs, Alex Zino, told the Nikkei newspaper that Japan had materials technology that could be useful in a new engine, specifically composites and heat-resistant superalloys. “We would like to see joint development of one engine for use as the powerplant of Japanese and British fighters.”

The full extent of cooperation had yet to be disclosed. Potential possibilities discussed at the time ranged from shared technologies and components to a common engine. The latter would entail both GCAP and F-X having to share to specific key performance requirements such as thrust class, PTMS, inlet design, LO shaping, bypass ratio, etc.

The decision to substantially involve UK suppliers into F-X, which would have cascading effects on many aspects of the aircraft’s overall design, heralded an emerging divergence with Lockheed Martin. For example, a joint engine would drive many of the PTMS and systems integration needs for the aircraft as well as its LO properties for inlet design. This seemingly conflicted with Japan’s earlier selection of Lockheed Martin which was to aid in overall systems integration and LO design expertise.

Formation of GCAP

On May 5^th, Japanese Prime Minister (PM) Fumio Kishida and UK PM Boris Johnson discussed future cooperation for potential collaboration for next generation fighters. In a piece for The Diplomat later that month, Takahashi Kosuke reported the Japanese Government was considering a partnership with the UK as well as BAE Systems. According to one unnamed LDP official, “Lockheed Martin was not so enthusiastic about developing Japan’s next-generation fighter.” The Sankei Shimbun had similarly reported earlier that month that negotiations with LM had reached an impasse and Japan decided to instead coordinate with the UK in consultation with the U.S. Government.

The following December, Takahashi wrote that Japan ultimately chose to join GCAP because of the similar schedules between F-X and GCAP, similar performance requirements, easing the burden of development costs across three nations, freedom to modify components, and the potential to achieve economies of scale both among partner nations and with export orders. A cooperative program with the U.S. was not anticipated to have any synergies with other programs such as NGAD.

Lockheed has disclosed few details about its perspective. However, the company was simultaneously pursuing both the USAF’s Next Generation Air Dominance (NGAD) and U.S. Navy’s F/A-XX programs. Even large primes have a limited pool of cleared top engineering talent to allocate for competitive programs. Consequently, it’s possible the potential cost of supporting F-X may have been judged as too great.

On Dec. 9, 2022, the UK, Italy, and Japan announced the formation of the GCAP program in a joint statement. UK PM Rishi Sunak said, the next generation of combat aircraft we design will protect us and our allies around the world by harnessing the strengths of our world beating defense industry – creating jobs while saving lives.” At the time, partner nations expected to deliver a business case in 2024, contract full scale development in 2025, and begin fielding GCAP in 2035.

Japan also issued a joint statement with the U.S. regarding expanded collaboration in “autonomous systems capabilities, which could complement Japan’s next fighter program among other platforms.” 

Features

GCAP will encompass a broader family of systems, illustrated above. Image Credit: Leonardo

Airframe

GCAP configuration evolution from Tempest & F-X. Credit: BAE Systems, Japan MoD.

As of the time of this writing, GCAP’s airframe configuration remains under study. Key expected attributes include LO, twin engines, long-range, and greater internal missile capacity than the F-35. The graphic above highlights the evolution of key features.

Notably, both Tempest and F-X concepts utilized lambda wing planforms and lacked horizontal tails – suggesting a prioritization of LO and range over maneuvering performance. Other common features include a chinned nose and forebody as well as serpentine intakes. Tempest renderings used a Diverterless Supersonic Inlet (DSI) configuration while the intakes of F-X were obscured. F-X renderings provide a more mature rear-quarter LO configuration using large V-tails to hide side-aspect views of the engines reminiscent of the YF-23. F-X’s engines also appeared to feature 2-D thrust vectoring nozzles like the F-22. The initial GCAP configuration in December 2022 blends key features of both Tempest and F-X.  

The July 2024 GCAP model shown at Farnborough Airshow features a new, wider span, delta wing. A BAE Systems press release describes the configuration as a “much more evolved design with a wingspan larger than previous concepts to improve the aerodynamics of the future combat aircraft.” Delta wings provide excellent supersonic performance as well as significant internal volume for fuel. Side aspect photos confirm the trailing edges of the wings obscure views of the engines in order to preserve LO.

The latest GCAP configuration broadly shares some commonality with the proposed FB-22 regional bomber concept (particularly FB-22-3 which retains the forward fuselage hood leading into large span delta wings). Bill Sweetman estimates a 50° sweep angle for GCAP’s leading edge – suggesting a prioritization of fuel economy during subsonic cruise over supercruise performance.[1] Some FB-22 configurations also featured a different sweep angle relative to the baseline F-22 optimized for additional range at the expense of supercruise. However, the FB-22 was still capable of dash speeds of Mach 1.5 and a top speed of Mach 1.92.

As with prior GCAP concepts, the model unveiled in July appears to utilize a pair of small vertical cropped trapezoidal tails – likely indicating an all-moving capability similar to the J-20. The incorporation of vertical tails also suggests less stringent broadband LO requirements when compared to some sixth-generation programs.

GCAP is also likely to be larger than the F-22 and at least a third larger than the Eurofighter Typhoon.[2] The aircraft’s size is largely driven by Japanese internal weapons bay and range requirements. In an April 2025, Group Captain Bill – the head of the UK MoD’s GCAP Requirement and Concepting team, announced GCAP would have twice the weapons capacity of the F-35. Captain Bill spoke on the Team Tempest Future Horizons podcast. (Note, Bill’s last name was withheld for security purposes.) Bill also said GCAP would have “extreme range”, suggesting “maybe getting across the Atlantic to America on internal fuel”, in contrast to the Typhoon which needs to be refueled three to four times to cover the same distance.

A transatlantic crossing capability could suggest an aircraft with similar internal fuel volume to the General Dynamics F-111A at 34,000 lbs. The F-111 also had an empty weight of 45,000 lbs. and maximum take-off weight (MTOW) of 92,500 lbs. The FB-22 similarly had an MTOW of 120,000 lbs. internal fuel capacity of 43,745 lbs. (equivalent to the empty weight of an F-22A) and combat radius of 1,500 to 2,000 nm.[3]

A GCAP model shown at the earlier JA 2024 featured a weapons bay arrangement similar to the F-22, with a large main weapons bay (MWB) located between the intakes as well as a pair of secondary side bays. The F-35 entered service with an internal capacity of four Raytheon AIM-120s. Lockheed has since developed the Sidekick upgrade to enable internal carriage of six AIM-120s. A total capacity for at least eight missiles would match earlier Japanese F-X requirements and concept studies. 

F-X requirements set by the Japanese Air Staff from September 2019 called for additional air-to-air Missile (AAM) capacity beyond that of the F-35. F-X percussor studies examined LO fighter concepts with four to six beyond visual range (BVR) missiles and a pair of within visual range (WVR) IR-guided missiles mounted in side-weapon bays. The F-X’s main weapons bay (MWB) geometry was sized to accommodate the Joint New Air-to-Air Missile (JNAAM or 共同新空対空ミサイル) – a MBDA Meteor missile derivative featuring a Mitsubishi Electric (MELCO) AESA seeker. Subaru conducted successful full-scale weapons bay wind tunnel testing at Mach 1.4 environments in 2018. 

The left image is from a 2017 article titled, “将来戦闘機に向けたウェポン内装システムに関する研究” or A Study on Weapon Interior System for Future Fighter Aircraft by Kei Okawa (大川啓), Naoyuki Tamura (田村尚之), Shinsuke Matsumoto (松本慎介) and Masayuki Aiba (饗庭昌行). Credit: Yu Kuwamoto

The design choice to feature a MWB with six BVR missiles and two side mounted IR missiles drives platform growth as it has downstream effects on the aircraft’s center of gravity, layout of the S-ducted intakes, etc. The F-X’s missile capacity also matched the F-22 which arguably remains GCAP’s closest in-service analogue.

Weapons

Weapons

GCAP’s primary mission is air superiority, but the aircraft is expected to undertake secondary strike and anti-surface warfare missions. All three GCAP nations operate the multi-role F-35. Primes have begun to define GCAP’s architecture and key weapons attributes as part its concept development phase. GCAP is expected to seamlessly integrate customer-specific and indigenously developed weapons as well as leveraging the latest developments in high-speed, extended-range, and miniaturized munitions; with the potential for Directed Energy Weapons (DEW) further in the future. 

At the 2019 Defense and Security Equipment International (DSEI) exhibition in London, MBDA showcased multiple current and future weapon concepts that could be integrated onto the RAF’s future combat aircraft^{2 / 3}. The RAF plans to “optimize” Meteor & SPEAR for carriage on Tempest⁴. Italy is also likely to select both weapons.

In September 2023, MBDA UK, MBDA Italia and Mitsubishi Electric Corporation agreed to collaborate and work towards an Effects Domain in support of the design of a core-platform for GCAP and ensure the seamless integration of weapons¹. The evidence thus far supports trends to integrate GCAP with long-range, stand-off munitions and smaller munitions to enable larger load-outs

The MBDA-led Future Cruise / Anti-Ship Weapon (FC/ASW) will almost certainly be integrated onto GCAP. There is also potential to carry a hypersonic weapon, with both cruise missile and ‘aeroballistic’ missile designs being possible. Such weapons tend to be relatively large and thus may require external carriage. However, evidence points to GCAP having ‘sizeable’ internal weapons bay(s), which may allow for their internal carriage thus reducing any impact on the aircraft’s low observability and cruise performance.

Chief of the Air Staff Air Chief Marshal Sir Richard Knighton has told a House of Commons committee on GCAP that Longer-range A/A missiles will be part of GCAP’s arsenal⁵. This is likely driven by the deployment of China’s PL-15 and PL-17, plus Russia’s R-37M. All three missiles (in particular the PL-17 & R-37M) are substantially larger weapons than Meteor, thus exemplifying the need to carry larger munitions.

MBDA’ SPEAR is described as a “mini cruise missile”, with its relatively small size will enable higher load-outs. Both the baseline SPEAR and SPEAR-EW will most likely be integrated onto GCAP. A maximum load-out has yet to be made public, but with GCAP having been described as having “twice” the payload of a F-35A, it can be estimated that the aircraft will be capable of carrying internally between 12 & 16 SPEARs.

MBDA’s two ‘micromissile’ concepts seemingly share a common design and are comparable in size and shape to a guided 70 mm rocket. The Air-to-Ground missile may be seen as an alternative for MBDA’s Brimstone missile, outfitted for internal carriage. The Hard Kill Defensive Aid System (HK-DAS) is designed to defend GCAP against airborne threats, including missiles. According to MBDA, the HK-DAS may actually be carried in dedicated launchers to maximize defensive coverage⁶. However, this would invite additional technical challenges and weight considerations during detailed design of the aircraft.

In FY24, Japan announced its Next Medium-Range Air-to-Air Guided Missile or 次期中距離空対空誘導弾 which effectively supersedes JNAAM. ATLA plans to spend approximately ¥30.1 billion ($200 million) on prototyping through to FY29 ahead of a mid-2030s fielding. Key requirements include a two-way data link and an improved seeker with enhanced performance against LO targets, according to the ATLA. Kyoto News reports the new missile is intended to have “better performance at a lower cost” than the Meteor.^[4] While preliminary and not necessary indicative of a future design, the initial rendering appears to lack a ramjet and includes large fore and aft control surfaces. In contrast, service provided renderings of the U.S.’ AIM-260 Joint Tactical Missile (JATM) indicate the use of cropped aft only control surfaces – potentially providing additional internal volume for rocket motor propellant.

To enable GCAP to replace Japan’s F-2 fleet in the anti-ship role, dedicated anti-ship missiles are likely to be integrated. By the time it enters service with the JASDF, the service will likely operate Norwegian-built Joint Strike Missile (JSM), alongside Japan’s own the supersonic ASM-3 ‘Kai’ and an air-launched derivative of the subsonic Improved Type 12. Integration of the two indigenously-developed missiles is considered most likely.

GCAP’s partner nations seek a design philosophy that facilitates capability expansion over the system’s lifespan⁷. In line with this, Rolls Royce is seeking to maximize electrical power generation to power the array of sensors and data analysis / processing capabilities envisioned for the platform. This can also be considered the first step to integrate a DEW such as a High Energy Lasers (HEL). The Royal Air Force has previously referred to “developing world-leading electrical generation technology and intelligent integrated power management to power Tempest’s advanced sensors and effects, particularly those which are laser-based.”

Avionics

GCAP is expected to feature a fused, multi-spectral sensor suite. The UK and Japan have multiple ongoing avionics programs that aim to mature key technologies for implementation into GCAP. These include AESA radars, digital beamforming technology (DBF), electronic support measures system (ESM), and sensor fusion.

A 757-200 modified by 2Excel Aviation will serve as the UK and Italy’s primary flying avionics laboratory under the Integrated Sensing and Non-Kinetic Effect system (ISANKE) and Integrated Communications Systems (ICS) program. Japan has its own program to modify a C-2 with indigenous systems.

The aim of these efforts is to establish sensor fusion and system integration industrial expertise. The Typhoon has arguably the oldest avionics suite of the major 4.5 generation fighter types – lacking an operational AESA until the delivery to the Kuwait Air Force of its initial Typhoons equipped with Captor-E Mark 0 radars in December 2021. The UK’s Captor-E European Common Radar System (ECRS) Mark 2 first flew in September 2024 and is expected to be operational on RAF Typhoons by 2030. Japan’s F-2 alternatively was the first fighter to feature an operational AESA with the J/APG-1 in 2000, but subsequent intellectual property disputes with the U.S. have dampened aspirations for further avionics improvements.

ISANKE (Integrated Sensing and Non-Kinetic Effect) – ICS Demonstrator

2Excel Aviation 757-200 named “Excalibur” taking flight in December 2024. Excalibur will serve as the Flying Test Bed (FTB) for the broader ISANKE program announced in 2022. ISANKE follows the prior Japan and Great Britain Universal Advanced RF system (JAGUAR) common ESM suite between F-X and Tempest.

Credit: Dave Turnbull, QinetiQ

In September 2021, 2Excel Aviation announced its Excalibur FTB demonstrator effort to support Tempest avionics development, with the company acquiring a pair of 757-200s. The first aircraft was disassembled during the initial design phase to create a digital twin and provide data for civil airworthiness registration. The second aircraft was acquired in 2023 and the MoD provided £115 million ($147 million) to modify the aircraft with Leonardo UK provisioned sensors and ten crew stations.

ISANKE’s sensor fusion architecture will integrate, fuse and process onboard data from the platform’s numerous avionics subsystems. In a 2022 interview with Aviation Week’s Tony Osborne, Andrew Howard – then Leonardo UK’s Director for Major Air Programs, described that the future Multi-Function Radio Frequency System (MRFS) AESA radar will be at the heart of ISANKE. MFRS is expected to provide longer-range performance, use a different type of antenna, and feature a new generation of materials relative to current generation fighter radars.

Osborne reports that little is known about the configuration of the MRFS, but Howard states that the materials used within it and other elements of the ISANKE system exceed the capabilities of Gallium Arsenide and Gallium Nitride semiconductors used in current AESA radars, and will offer “substantial improvements,” over those used on the Eurofighter Typhoon. The materials enable miniaturization of the components, boost conductivity and allow improved levels of heat management for LO operation. As well as the traditional roles such as fire control, the sensor is also likely to be capable of electronic attack.

Other onboard elements to be linked into ISANKE include the defensive aids suite, infrared search and track (IRST), and electro-optical (EO) targeting systems. Sensors will be integrated and embedded across the airframe, with miniaturization enabling greater capacity to “create a bigger output than we have ever achieved previously,” Howard suggests.

The development of the ISANKE system is also being shaped around the need for exportability so that it can be adapted for different customers. The system will likely incorporate the Pyramid open-systems architecture.

Excalibur is expected to fly with an initial sensor suite by the July 2026 Farnborough Airshow. Additional sensors would be integrated in phases. Leonardo is also adopting digital tools to speed up ISANKE’s development.

Japan C-2 FTB

Japan’s FY19 budget announced a ¥5.7 billion ($42 million in FY25) study into mission system integration for future fighters. Jwing reported in September 2019 that the MoD planned to furnish a Kawasaki C-2 to serve as an FTB for F-X. The project was expected to cost ¥24.9 billion ($186 million in FY25) and flight testing would take place between FY23 and FY24. As of the time of this writing, Japanese government documentation indicates ¥16.5 billion ($110 million) has been spent between FY22-24 on “research and prototyping of mission systems integration for fighter aircraft, etc.” or 戦闘機等のミッションシステム・インテグレーションの研究試作.[5][6]

MELCO has previously led many of Japan’s next generation fighter self-protection R&D efforts. Toshiba, NEC and Northrop Grumman had also participated with various F-X avionics systems. The following is a list of major Japanese R&D efforts involving fighter self-protection systems:

• 2002-2009 study on an advanced, multi-function antenna. The study concluded with anechoic chamber testing under simulated conditions.
• $170 million 2010-2018 integrated sensor study that included ESM.
• 2011 flight test of a new tail-mounted MELCO ESM antenna aboard F-2 testbed 63-8502.
• $96.67 million 2012-2020 effort to develop missile approach warning sensor (MAWS) technology.
• $36.85 million project running from 2013-2018 to further advanced radio frequency (RF) simulation research including LO antenna design and 3D high precision geolocation.

Refer to the F-X profile for additional details.

Pre-GCAP Avionics Collaboration Programs

UK-Japan Digital beamforming (DBF) technology

In existing AESAs, Transmitter Receiver Modules (TRM) are organized into subgroups, which are then linked to a receiver at the back of the array. The signal runs through an analog-to-digital conversion process via coaxial cables on the way to the signal processor – a method which induces signal loss. The size of existing receivers makes rear mounting a necessity. Leonardo hopes to miniaturize the receivers associated with each TRM group, enabling them to be mounted forward in the array and eliminate the need for coaxial cables. This would allow digitization of the signal much earlier in the receive chain after which the signal is transmitted directly via fiberoptic cable to the signal processor (vs. an intermediate step). Since digital signals can be limitlessly copied without loss, the data can be processed to create simultaneous beams in many directions, all benefiting from continuous energy collection by the complete array. This is known as “digital beamforming” (DBF). Miniaturization of the receivers would also facilitate an increase in the number of TRMs. However, even with element-level DBF, the transmitted energy is still limited by the power and cooling of the radar. Japan’s FY21 budget request outlines a $39 million effort to collaborate with the UK on DBF.

JAGUAR Electronic Support Measures System

In March 2018, the UK and Japan announced the launch of the Japan and Great Britain Universal Advanced RF system (JAGUAR) – a common ESM system for both Tempest and F-X. Both countries signed a letter of arrangement on February 15, 2022. The UK MoD announced,

“The universal radio frequency sensor technology, known as ‘JAGUAR’, could enable the Armed Forces to better detect future threats from air, land and sea, quickly and accurately locating targets and denying surveillance technology operated by our adversaries. With joint work on the project scheduled to start in April, JAGUAR is expected to create 75 jobs across the UK, including 40 highly skilled engineering jobs at Leonardo’s Edinburgh site…Designing, building and evaluating the JAGUAR system will take around five years, involving input from Leonardo UK and Japanese industry. Two demonstrators will be built within the project, one in each country, with the work and learning shared to maximize national expertise.”

Engines

GCAP is anticipated to be powered by a pair of turbofans jointly developed between Rolls-Royce (RR), Avio Aero, and IHI Corporation. In April 2025, RR’s Mark Tivey – Future Programs Business Development Director, confirmed to Aviation Week’s Tony Osborne that GCAP would not utilize adaptive cycle technology, “We understand the adaptive engine, and we have looked at that technology for the mission set this aircraft will face, and we do not believe it earns its way onto the aircraft.” Tivey added, “You will get benefits from such an engine, an economy mode and a war fighting mode, but the trade between the cost and the capability is a pretty fine one, and we do not think it is justified in the mission set we are looking for GCAP.”

GCAP will alternatively utilize a more conventional two-spool turbofan configuration with optimizations for power and thermal management. RR had previously discussed “1 MW” class electrical power generation capability for Tempest (equivalent to the 787). Other expected features include high thrust to weight ratio, 1,800°C+ operating temperature, and low specific fuel consumption. As of the time of this writing, specific performance targets have yet to be disclosed. However, a thrust class of approximately 30,000-35,000 lbf. similar to the P&W F119 is plausible given the expected size of GCAP.

At that time, Tivey confirmed all three nations were working toward a demonstrator in the coming months, “The engine demonstrator is a key part of our technology maturation process…We are not yet designing the final product, but we have been maturing our technologies so that we are in a position that is much more robust going into the program that we have been before.” Workshare for the demonstrator includes an Avio Aero low-pressure turbine, IHI Corporation compressor, and RR combustor as well as the high-pressure turbine and exhaust nozzles. The engine’s core design will be informed by RR’s Advance1 demonstrator and the Pearl 10X business jet engine, a medium bypass powerplant based on the company’s Advance 2 demonstrator.

Osborne also reports other possible features include a multi-stage, wide chord distortion-tolerant blisked fan, embedded starter generator, a lightweight, high temperature core and fully integrated heat management system. The latter may leverage prior RR work under the Surface Heat Exchangers for Aero Engines (SHEFAE) program.

Additive layer manufacturing (ALM), such as 3D printed combustor tiles, is also expected to be a key part of the next generation combustor. ALM has expedited testing of multiple combustor designs to facilitate improved understanding of airflow and cooling dynamics between the inside and outside of the combustor wall. This in turn enables a reduction in cooling airflow from the core which permits a reduced diameter engine core thereby minimizing overall engine mass and diameter – resulting in lower overall system weight and drag.   

Pre-GCAP UK-Japan Engine Cooperation

On Dec. 22^nd, 2021, the UK and Japan announced a joint partnership to explore common engine technologies, and possibly components, to share across the then Tempest and MHI F-X programs. The UK would contribute an initial investment of £30 million with a further £230 million for a full-scale demonstrator. The project will likely run through the mid-2020s. Two days later on Dec. 24, 2021, Japan’s Acquisition Technology and Logistics Agency (ATLA) issued an RFI for low bypass ratio engines to international primes. The document specified “technical information required for integration of power and thermal management systems, stealth and flight control”.

The announcement comes after nearly two years of discussions. In November 2020, RR director of future programs, Alex Zino, told Nikkei that Japan had materials technology that could be useful in a new engine, specifically composites and heat-resistant superalloys. “We would like to see joint development of one engine for use as the powerplant of Japanese and British fighters.”

IHI has led Japanese R&D efforts aimed at next-generation fighter engines since the 1990s. Total Japanese industry investment reached ¥51 billion ($492 million) by the end of 2020 and culminated in the development of the IHI XF9-1 demonstrator. The XF9-1 can operate at temperatures higher than 1800°C – 270°C more than the EJ200, as a result of an advanced combustor, fifth generation single-crystal nickel superalloy turbine rotor blades and ceramic matrix composite material (CMC) shroud. The higher operating temperatures enable the XF9-1 to produce more than 33,000 lbf. (15 metric tons+) of thrust.

The XF9-1 layout follows the general configuration of the F119, including a sophisticated arrangement of inlet vanes designed to disrupt radar reflections. The engine is also similarly sized with an inlet diameter of approximately 39 inches. The XF9-1 has substantial cooling capacity and can generate up to 180 kW of electrical power, another key capability of interest to RR for the then Team Tempest. Notably however, the XF9-1 is merely a test article and not of a production worthy configuration.

Engine Electrical Power Efforts

Prior to GCAP, RR discussed achieving “787 class” (1 MW) electrical power generation for Tempest – a tenfold increase over the Typhoon. Engines are critical source of electrical power and systems cooling for aircraft – which is crucially important for LO fighters given the need to suppress their IR signature while accommodating growing avionics requirements. Anticipating this growing demand, RR began its electrical embedded starter generator (E2SG) program in 2014 as part of the FCAS TI. Existing fighter engines generate electrical power through an external gearbox on the engine, which drives a generator. E2SG aims to eliminate the gearbox by integrating an internal electrical starter generator within the core of the engine.

The first phase of the E2SG program embedded an engine starter-generator into the core of an Adour engine. During the second phase in 2017, RR installed an additional generator connected to the other engine spool. RR engineers also added an energy storage system in the electrical network as well as a system to manage the supply of power between the systems.

In January 2020, Osborne reported that the company was planning a third phase to add “new technologies in all parts of the gas turbine” including twin spool embedded generation to reach higher power levels, an advanced thermal management system and energy storage, which the company says will be tailored to the “duty cycle of future fighter.” Engineers had also planned to install a power management system capable of optimizing the performance of both the gas turbine and the power and thermal management system.

RR was supporting other critical enablers of Tempest including thermal management and the dissipation of aircraft heat through the engines as part of the platform’s IR signature management. RR also announced it was working with Reaction Engines to study the potential benefits of Reaction’s pre-cooler heat exchanger technology on a fighter engine.

Collaborative Combat Aircraft (CCA) Concepts

As of the time of this writing, GCAP does not feature a single unified CCA concept between all three nations. John Stocker, BAE Systems business development director for future combat air systems explained that because GCAP is intended to be a system of systems, varying country specific CCAs will not be an issue. “We have a common view of that requirement. We may not today have plans in place between the three nations around us, and we may never have the same CCA or we may do. But the important thing is a core assumption that CCA will operate as part of that integrated system going forward.” As of the time of this writing, Japan arguably has the most clearly defined CCA ambitions followed by the UK. Italy has largely been silent on its prospects of integrating future CCAs into GCAP.

Japan

The ATLA first expressed interest in a CCA like capability in 2012 with the release of its R&D vision statement for future fighter aircraft (将来の戦闘機に関する研究開発ビジョン. This was reaffirmed in 2016 with the publication of its future unmanned R&D vision statement (将来無人装備に関する研究開発ビジョン～航空無人機を中心に) which included plans to develop technologies related to combat oriented UAVs. Credit ATLA

Prior to GCAP, during the F-X program, Sankei reported Japan’s MoD would start full-scale development of an unmanned complement to F-X in 2021. Flight testing of a small demonstrator would follow in FY2024. The paper reported three UAVs could be paired with each F-X to act as a sensor and weapon platforms. Nikkei later verified this, reporting in January 2021 that the MoD sought a maneuverable, remote controlled complement to F-X that could be fielded as early as 2035, with design work concluding by FY2025. The unmanned asset would act as a “force multiplier” for the limited F-X fleet and help offset the numerical superiority of advanced Chinese fourth and fifth generation fighters. Subaru will be responsible for developing the flight control systems while MHI and MELCO would develop a networking and data sharing system. Participation with the U.S. or UK would be considered.

The earlier i3 studies studied Manned-Unmanned Teaming (MUM-T) Concept of Operations (CONOPS) featuring cooperative engagement, launch on remote, and wide field of regard, and multi-spectral sensors. While modern air-to-air BVR weapons advertise fire and forget capability, in practice mid-course updates are required to increase probability of kill (PK) as the missile’s seeker is inherently limited in detection power and duration (battery power consumption). This is particularly relevant in the prosecution of LO targets.

Following the formation of GCAP, Japan and the U.S. issued a joint statement regarding expanded collaboration in “autonomous systems capabilities, which could complement Japan’s next fighter program among other platforms.” On May 3, 2024, Japan, Australia, and the U.S. signed an agreement to facilitate future CCA collaboration.

Full-scale MHI ARMDC-20X expendable unmanned system. MHI’s attritable CCA concept is shown in a sub-scale model to the right. Credit: Chen Chuanren, Aviation Week. 

In October 2024, MHI unveiled its company funded CCA concept at Japan Aerospace 2024, with three variants planned based around a common layout. The ISR and CCA (戦闘支援無人機) versions would be launched and recovered from airfields while the 4 m long expendable type would be launched from aerial platforms. The expendable drone is designated as the Affordable Raid Missile Drone Concept (ARMDC)-20X and is similar in layout to GA-ASI’s Gambit.[7] MHI marketing materials illustrate the CCA variant assisting next generation fighters by providing additional situational awareness and missile capacity. MHI Deputy Director for UAVs – Takahiro Katoji, told Aviation Week’s Chen Chuanren that the company had only recently begun to study CCAs. MHI’s attritable CCA concept features a prominent chine line running from its sharp nose down the fillet to a pair of trapezoidal wings. The design also incorporates diverterless supersonic intakes and a pair of canted vertical tails.

In order to mature associated technologies, MHI plans to flight test a pair of small (3 m in length) target drone-like demonstrators in November 2025. One airframe will be optimized for ISR while the other’s features are more reminiscent of fifth generation aircraft with the exception of its engines. ATLA will conduct additional flight testing between FY26 and FY27.[8][9][10]

United Kingdom

In March 2024, the UK’s Sunak Government released its Autonomous Collaborative Platforms (ACP) white paper. The document outlines the service’s thinking and categorization of the market into three tiers (1-3) ostensibly echoing the U.S.’ expendable, attritable, and exquisite schema. The strategy calls on the RAF to focus on the development of Tier 1 platforms within a year and a focus on attritable Tier 2 systems by the 2030s. Notably, the Northern Ireland-based Spirit Aerosystems was selected to develop an attritable class CCA under Project Mosquito in 2021 in partnership with Northrop Grumman, but the project was ultimately canceled after the RAF concluded that it would not meet cost requirements. 

BAE Systems unveiled its Concept 2 attritable (left in the foreground) and Concept 1 expendable (background) ACPs in 2022. In February 2024, the company released a reworked Concept 2 shown to the right ahead of the release of the UK’s ACP strategy. Image Credit: BAE Systems.

At the July 2022 Farnborough air show, following the cancelation of Project Mosquito, BAE Systems pitched its own Concept 1 and 2 UAS. Basic features included:

Concept 1

• Minimal consideration given to RCS reduction, target drone like planform, with a likely emphasis on low-cost & ease of manufacturing features
• Performance
  • 40 kg payload
    • EW, ISR, air-to-ground payloads
  • Rail launch, parachute landing
  • 30,000 ft. service ceiling
  • 4 hrs. endurance
  • 0.5 cruise speed

Concept 2

• Lambda wing, V-tail planform with dorsal inlet and sharp chinned nose. Overall arrangement similar to the GA-ASI MQ-20
• Performance
  • 3,500 kg MTOW (7,716 lbs.)
  • 500 kg internal payload
    • 4 MBDA Spear class weapons or 2 MBDA Meteor class missiles
    • Radar, EW, EO/IR sensor payloads
  • Conventional take-off & recovery
  • 5 hrs. endurance
  • 0.75+ cruise speed
  • 40,000 ft. service ceiling

BAE’s reworked 2024 Concept 2 shares many features with Northrop’s High Stealth Fighter concept, which eventually became the YF-23, with its “platypus” nose and diamond wings. More broadly, the planform appears to de-emphasize the ISR mission relative to the 2022 concept.

Speaking at the 2024 World Defense Show in Riyadh, BAE Systems’ Steve Reeves (head of business development and strategy for platforms within Falcon Works) remarked, “So, what you see here is a more optimized design, not just from a [low observable perspective], but just as importantly, the cost point to the customer in manufacturing. At the heart of this is developing affordable mass which is really the step change in how we can do things differently.” 

Production & Delivery History

Key Highlights

• EMD is expected to cost around $43.5 billion.
  • A full-scale development contract is expected by the end of 2025, followed by flying demonstrators in the late 2020s, 10 prototypes, and IOC by 2035
• A new Joint Venture (JV) will be formed with equal workshare of 33.3% between national industry primes by mid-2025.
• Core nations are expected to buy over 300 aircraft, according to Leonardo.
• Affordability arguably remains the greatest challenge to the viability of GCAP, followed by industrial workshare concerns. A solution to one problem may exacerbate the other.

Status of the GCAP program as of March 2025. Image Credit: Leonardo

Contracting Structure

GCAP currently remains in a relatively early concept development phase. A full-scale development contract (equivalent to engineering, manufacturing, development) is expected in 2025. From the government side, the program will be managed by the GCAP International Government Organization (GIGO) based in Reading, England.

Work will be undertaken by a new JV comprised of each nation’s lead primes with a 33.3% share including: BAE Systems for the UK, Leonardo for Italy, and Japan Aircraft industrial Enhancement Co. Ltd. (JAEIC) for Japan. JAEIC is effectively a spin-off of MHI founded in July 2024 in partnership with the Society for Japanese Aerospace Companies (SJAC). The JV’s headquarters will also be based in England, though each country is expected to maintain a local development center in Warton for the UK, Turin for Italy, and Nagoya for Japan. The JV’s structure and authorities take into account lessons learned from prior programs. According to BAE Managing Director of FCAS Herman Claesen, “This one will have design authority, and it will be properly empowered to own the program more so than we’ve seen in the past.” The as-yet unnamed company is expected to form by mid-2025 and will be accountable for the design, development and delivery of the aircraft. In addition, the JV will be the Design Authority (DA) for the aircraft throughout its life, until at least 2070.

Japan is largely driving the 2035 initial operational capability (IOC) target given its threat environment and the age of its F-2s. Several risk factors threaten the viability of the overall program as well as the compressed 10-year EMD schedule. The most significant of which is affordability followed by industrial workshare agreements. Confoundingly, a solution to one problem may exacerbate the other. For example, adding new partners such as Saudi Arabia could improve the financial stability of the program at the risk of diluting workshare among existing participants. Technological and capability burdens arguably also represent a significant, though secondary challenge.

Affordability

The European partners of GCAP currently face significant budgetary constraints with competing programs. Both countries have sought to bolster near-term procurements following the conflict in Ukraine. Italy has discussed the acquisition of additional Typhoons, F-35s, and main battle tanks. These aspirations have arguably not been matched by corresponding increases in defense budgets. However, the deterioration of transatlantic ties may compel additional growth subject to fiscal realities.

For example, Italy has moderately raised defense spending starting from the 2020s to 1.54% of GDP or €29.18 billion ($30.89) billion. However, NATO reports that procurement and R&D only account for 22% of Italian defense outlays with personnel accounting the majority at 59%. Italy has not pledged to increase defense spending to the 2% NATO GDP target as of the time of this writing.

UK Defense planning scenarios. Credit: Craig Caffery, Aviation Week

The UK MoD’s budget similarly faces significant pressures both internally and externally – culminating in a 22% real term reduction in defense budgets from £57.1 billion in 2009-2010 to £44.6 billion in 2018-2019. UK Defense budgets returned to early 2010 levels by the start of the 2020s. In February 2025, PM Keir Starmer pledged to increase defense spending to 2.5% of GDP by 2027 or to £87 billion ($110 billion). A follow-on increase to 3% of GDP was also discussed as an option for the next parliament between 2029-2034 subject to future economic and fiscal conditions.

Aviation Week’s Craig Caffery notes that increasing defense outlays to 2.5% of GDP would translate to an additional £6-7 billion ($7.6-8.9 billion) in real terms spent for core combat capabilities. Given the existing shortfalls in defense spending and years of accumulated unfunded service priorities, Caffery notes “…the budget increase is likely only to return military capabilities to where they are currently expected to be rather than to fund new initiatives.” However, he notes raising spending to 3% of GDP would translate to a 45% increase in defense spending in real terms. Achieving such a target by the early 2030s is likely critical to translating GCAP from EMD into production.

In 2022, Japan’s then PM Fumio Kishida pledged to increase defense spending to 2% of GDP by 2027. Spending across the FY22-27 Defense Buildup Program totaled ¥43 trillion. Japan has since followed through with significant year-over-year (YoY) percent increases to its defense budgets, but the subsequent devaluation of the Yen has significantly undercut Tokyo’s purchasing power.

The MoD originally planned for an exchange rate of 108:1 with the dollar which is now 147:1 as of the time of this writing – marking a 36% decrease in purchasing power over the FY23-27 period from nearly $400 billion to $293 billion. Foreign import programs are expected to be the most affected – though many domestic Japanese programs also utilize internationally sourced subcomponents. It’s unclear if any accommodation will be made in GCAP’s contracting structure to account for fluctuations in foreign currency.

Development Costs

As of the time of this writing, no official and compressive accounting of GCAP’s program costs has been disclosed. Affordability challenges are expected to be acute during both development and procurement.

A Leonardo strategy document released in March 2025 expects GCAP’s EMD to cost “~ €40 billion” ($43.5 billion).[11] Such a figure is consistent with a November 2023 disclosure by the UK MoD that it would spend over £12 billion ($15 billion) to develop GCAP over the next ten years (2033). Assuming the continuation of R&D until at least GCAP’s IOC in 2035 and an equal cost sharing agreement between partners, total GCAP EMD expenditures may exceed $45 billion. Such a figure would be consistent with the upper-bound limit of historical programs (all values in adjusted FY25 dollars):

• The UK contributed $11.4 billion to develop the Eurofighter Typhoon. With the UK funding 33% of EMD, total development costs amount to $34.5 billion.
• F-22 pre-EMD R&D spending for the Advanced Tactical Tighter (ATF) program reached $6.4 billion not including an additional $4 billion provided by industry. Total RDT&E outlays between EMD and IOC reached $40.7 billion.
• The NGAD FoS RDT&E is expected to cost approximately $40 billion including $6 billion pre-EMD, $21.5 billion for EMD, $3 billion for adaptive cycle engines, and $9.2 billion for CCAs.

As of 2025, GCAP nations have spent approximately $8 billion pre-EMD as shown on the chart above with Japan alone accounting for half that share. Note, both Japan and Italy provide YoY funding totals including for pre-GCAP F-X and Tempest activities. The UK has only provided that the MoD “has committed £2 billion to GCAP since 2021” through to 2025. Therefore, UK funding depicted above assumes an average to get YoY totals. 

Credit: Aviation Week

EMD funding will support multiple demonstrators which are expected to take flight by the late 2020s. These include both a BAE Systems-RR demonstrator validating LO intake techniques and an Excalibur Boeing 757 avionics prototype. Japan also maintains a C-2 FTB.

Production

GCAP partner nations have yet to disclose a Program of Record (PoR) or procurement objective. However, in March 2025, Leonardo CEO Robert Cingolani said that he expected core GCAP member countries (i.e. not including exports) would order over 300 aircraft. He also confirmed that full-scale development would also include a total of ten prototypes.

Cingolani’s remarks imply an expectation for a mirrored replacement program of each nation’s existing fighter fleets. Each country operates approximately 100 legacy aircraft which are in need of replacement. Japan’s fleet 68 upgraded F-15 Japan Super Interceptors (JSIs) could also conceivably be replaced after its F-2 fleet in the 2040s or 2050s. Assuming a mirrored replacement program, the UK would procure 106, Italy 93, and Japan between 90-158 aircraft. However, GCAP’s high expected flyaway costs and the emergence of CCAs could apply downward pressure to the PoR.

GCAP nations may reduce their PoR to reflect a broader high-low mix force structure benefitting from CCAs. A mirrored fighter replacement effort with a full complement of a pair of CCAs per manned fighter would cost $2.88 billion relative to the affordable example above at $1.84 billion. Image Credit: Aviation Week

As of the time of this writing, no official GCAP flyway cost estimate is available. Historically, an aircraft’s empty weight has been strongly correlated to its flyaway cost. Increases in empty weight are often indicative of greater complexity and capability requirements. For example, the 18,000 lbs. single-engine F-16 was intended to fulfill less demanding missions than the 28,000 lbs., twin-engine, air superiority optimized F-15. GCAP’s LO, internal weapons bay capacity, and range requirements all suggest a large fighter with a correspondingly high empty weight. GCAP’s closest in-service analogue is the F-22 at 44,000 lbs. which has an adjusted FY25 fly-away cost of $225 million.

GCAP may benefit from digital engineering and other cost saving technologies – though the effect of those on more recent programs has been oversold according to then USAF Secretary Frank Kendall. In May of 2023, he explained, “My best feel for that is, it’s on the order of 20%, as a ballpark number.” Of note, Northrop Grumman expects to take a $1.56 billion loss on the first five B-21 firm-fixed-price B-21 LRIP lots despite the incorporation of such technologies.

Achieving economies of scale is a proven method of reducing flyaway costs. Raptor production peaked at a rate of two airframes per month. Sustaining production at a similar level for GCAP (18-24 aircraft per year) is likely key for affordability and avoiding a procurement “death spiral”. In contrast, the GCAP nations cumulatively took delivery of between 9-14 F-35s per year between 2020-2024. Of note, the UK concluded deliveries of Tranche 3 Typhoons in 2019 and Italy in 2020. Therefore, using F-22 prices, sustaining GCAP production could require a nearly four-fold increase in fighter procurement spending to $4-$5.4 billion annually.

A 2011 NAO report estimated the UK would spend £13.5 billion ($24.9 billion in adjusted terms) to procure 160 Typhoons. A mirrored replacement program of the 106 aircraft left in service could cost $23.8 billion using F-22 prices. A reduced buy of 80 aircraft accounting for the expected future role of CCAs would cost $18 billion.

The UK’s July 2021 Infrastructure Project Authority (IPA) report and February 2022 NAO Audit of the UK Defence Equipment Plan (DEP) provides the most holistic accounting of overall costs despite pre-dating GCAP. The IPA lists the lifecycle cost of FCAS at £72 bn ($93.7 bn), through 2070. The more recent NAO DEP audit report states £8.65 bn ($11.6 billion) would be spent to develop the system over 10 years.

Endnotes