There are many different visions of the future of UK aerospace technology. But the reality tucked away on the northern fringes of Cotswold Airport near Kemble, England, is at first glance hardly forward-looking.
- Startups leading drive to hydrogen power for regionals
- Established industry seeks role on sustainable large airliners
Under the curved roof of a World War II-era hangar, a handful of technicians armed with wrenches and screwdrivers are working on a Dornier 228 built in 1985. Yet it is here, and in similar places, where tomorrow’s zero-carbon aircraft are taking shape.
The UK has set a goal of carbon-neutral air travel by 2050, with the ambition of net-zero-emission domestic aviation by 2030. Corporate commitments and government road maps plot a direction of travel, but large gaps remain between these aspirations and the technologies, processes and people needed to make them realities.
There is no shortage of visible effort to bridge those gaps. High-level initiatives such as the Aerospace Technology Institute’s (ATI) two-year FlyZero program have sketched sector-wide strategies intended to help ensure the UK’s aerospace sector is well-placed to win significant work on the next generation of green aircraft. Research programs within companies are targeting the underpinning technologies and industrial processes.
Alongside those longer-term programs, innovative projects from startups—such as ZeroAvia’s integration of hydrogen-electric propulsion onto the 228 at Kemble—could see zero-emission powertrains flying much sooner on smaller aircraft serving regional routes in the UK. Sustainable aviation fuel (SAF) offers the potential to reduce life-cycle carbon emissions from today’s fleets, but only if production can be scaled up dramatically. Various hybrid approaches promise substantial reductions, but with restrictions on utility. Each requires major amounts of time, people and money.
Aviation Week interviewed professionals across the UK aerospace sector to find out what is in place and working well as the country pursues the goal of zero-carbon commercial flight, what still needs to be done, and what it all might mean for a country that has not built a new passenger aircraft in a generation.
The Energy Problem
Decarbonizing aviation is not just a technical challenge. Everything from flying hardware and ground infrastructure to airspace management and industrial strategy must adapt. At the heart of it all is the problem of energy density.
“Around 200 companies are touting different options for battery-powered flight,” says Simon Webb, a 20-year veteran of Rolls-Royce who led the FlyZero propulsion and energy team and is now the ATI’s head of zero-carbon strategy. “In terms of use of the aircraft, it’s a good environmental solution; but at the moment the amount of energy you can pack into a battery is around 40 times worse than kerosene.”
Radical improvements in battery energy density are unlikely. A doubling or even tripling may be possible, but the 30- or 40-fold increase required to achieve meaningful range for a large commercial aircraft would defy physics.
FlyZero looked at ammonia—which brings too many difficult-to-solve problems—and gaseous hydrogen. In a different part of the airliner market, Cranfield Aerospace Solutions (CAeS) was having the same discussions in 2021, selecting gaseous hydrogen for its Project Fresson demonstrator. The program aims to retrofit the nine-passenger Britten-Norman Islander with fuel-cell-powered electric motors and underwing hydrogen tanks. First flight is planned for 2023, and CAeS intends to move the capability into production.
“We looked at batteries, we looked at hybrid electric, and we looked at hydrogen,” says CAeS CEO Paul Hutton. “We needed 60 min. of flight plus 45 min. in reserve. The only solution that got us the endurance—and was not less CO2 but zero—was hydrogen.”
The company aims to have the first retrofitted aircraft in service with a regional operator by 2025. Scotland’s Loganair has been in discussions with CAeS on electrifying its Islander fleet since 2018. It is unlikely the airports it wants to serve—on islands in the Orkneys and Hebrides—would see a reliable supply of liquid hydrogen within the next three years.
“One of the reasons we’ve gone for gaseous is because it’s relatively straightforward to supply,” Hutton says. “We know that on a truck, in bottles, we can deliver gaseous to any little airfield anywhere, however remote.”
For aircraft larger than 19 seats, gaseous hydrogen is less attractive. Pressurized tanks containing sufficient fuel for longer flights would be prohibitively heavy and take up too much space in the fuselage. SAF can help reduce emissions now, but supply is low and even a 100% SAF flight still would emit carbon. FlyZero concluded that liquid hydrogen (LH2) offered the most potential for longer-range passenger aircraft (which it says account for 90% of CO2 emissions), while posing challenges that, while significant, should be surmountable.
Unlike the solutions proposed by CAeS or ZeroAvia for existing airframes, however, range and payload considerations mean a clean-sheet design will be required. Tanks, cooling systems and fuel cells must be integrated at the earliest stage of design. This is prompting companies to revise how early-stage R&D is carried out.
“The Wing of Tomorrow program is focused on thinking about what technologies we need for the wings of future Airbus aircraft,” says Sue Partridge, head of the Airbus site at Filton, England. “That could be a more efficient conventional SAF aircraft, it could be a hydrogen aircraft, or it could be any combination of the different choices we have today.
“We haven’t made those choices yet, and we don’t intend to make those choices yet,” she continues. “What we’re working on is developing the technologies to give the business the options to make those choices.”
In May, Airbus opened a Zero Emission Development Center at Filton, whose staff plans to work closely with the Wing of Tomorrow program on how integrating hydrogen systems into aircraft can leverage efficiency, production rates and cost improvements achieved through innovative wing design.
“The center will focus on the fuel distribution and management system,” Partridge says. “How do we get the fuel from a hydrogen tank through the airframe to the propulsion system, wherever that may be, and how do we integrate that into the airframe? The wing and the fuel system really go hand in hand, which is why it makes sense to have those engineers working closely together here at Filton.”
Multiple Visions
With so many different moving parts, each a vital component of a zero-carbon ecosystem but all following different timetables, an overarching strategy is vital. UK government policy has set the 2030 and 2050 targets. The Jet Zero Council, a government-industry body established in 2020, has a mandate to be “the catalyst for zero-emission flight across the Atlantic.”
The council’s membership of 37 includes parliamentarians and senior executives from industry, trade associations, academia, airports, airlines and fuel providers. With a focus on long-distance flight, the membership reflects those parts of UK industry involved in the manufacture and use of large airliners. ZeroAvia CEO Val Miftakhov is the only representative of a startup with a seat at the table, while Loganair CEO Jonathan Hinckles is the only member from an airline operating exclusively in the regional and subregional sectors.
The ATI offers more focused sector-specific direction and allocates funding from the UK Department for Business, Energy and Industrial Strategy (BEIS) to lower technology-readiness-level projects. Its FlyZero initiative has provided more granularity for achieving wider national aspirations and generated notional designs for regional, single-aisle and widebody hydrogen airliners.
These are far from the only entities engaged in high-level preparations, and more documents, plans and consultations are emerging almost by the day. While the UK aerospace industry will not be short of advice, companies in the sector—particularly smaller ones—may struggle to assess which initiatives are likely to last the course and which entities represent the most useful strategic partners or advisors.
“If you had a full-time job, 24 hr. a day, seven days a week of reading every initiative on sustainable travel, you would fill more than one lifetime,” says John Pritchard, president of GKN’s civil airframe business. “Let’s look at Farnborough [International Airshow], for example. You’ll have an AGP [Aerospace Growth Partner-ship, a government-industry sector-strategy body] strategy. BEIS will have the net-zero transition plan. The UK Department for Trade will have its jet-zero strategy. ATI has its technology strategy. There also will be an ADS [UK aerospace and defense trade body] strategy, and we at GKN are personally involved in a number of these. And that’s just in the UK for Farnborough. Every company has its own take as well.”
Some things that may be missing, argues CAeS Chief Strategy Officer Jenny Kavanagh, are medium-term goals. “We have the net-zero 2050; we have zero-emission domestic flight by 2030. Those are two massive targets,” she says. “What should we be doing now? And that’s ‘doing’ now, not reporting on what is required. We’ve got zero-emission domestic flight by 2030-—how about zero-emission flight under a certain range by 2026-27? Really start pushing industry. Industry loves targets.”
There nevertheless is praise for the leadership being shown. The ATI, in particular, is performing a role that goes beyond setting an agenda and handing out BEIS funding.
“There have been a number of times ATI has come to us and said: ‘Go and speak to this company’; ‘Go and partner with this company,’ not necessarily on the competition side, but on the collaboration side,” says Anmol Manohar, head of product and strategy at Blue Bear Systems Research, a small uncrewed-systems specialist leading Project Inception to develop a scalable family of ducted-fan electric engines. “We might not know of all the other companies and what they’re doing, but if we partner together, the whole would be greater than the sum of the parts. That’s what the ATI has done well.”
The plethora of initiatives may raise as many questions as they answer. GKN’s Pritchard, who is an AGP board member, says it can be tough even for experienced teams in larger companies to navigate the various layers of planning. And the stakes are only getting higher.
“I’m in the middle of it, and sometimes it’s difficult,” he says. “We have a situation of complexity from a UK perspective, post-Brexit, of how all of this comes together in a world of global, European and U.S. [initiatives] and how the UK plays a role still and has relevancy post-Brexit in this global race. Because I think it is a race for sustainable flight.”
SubRegional sMEs
High-level strategy and the efforts of OEMs and Tier 1 suppliers are concentrated on the large commercial aircraft segment, where emissions are the highest and business opportunities the greatest. Those efforts are vital but unlikely to result in zero-emission flight in the short-to-medium term.
enabling sustainable aviation. Credit: GKN Aerospace
At the subregional level of small and midsize enterprises (SME), though, tangible progress is much nearer. Indeed, the first flight of ZeroAvia’s modified Dornier may have occurred before this edition of AW&ST was published, according to European Vice President Sergey Kiselev.
“We like to set ambitious but realistic goals, though we understand we will discover unknowns. That’s the nature of R&D,” he says. “But what differentiates us from many other people is that we actually do things. For us now, it’s important to demonstrate we can fly on hydrogen.”
The company’s Dornier will fly with one conventional turboprop and one hydrogen-electric powertrain. The electric motor will drive a five-blade propeller, while the legacy Honeywell TPE331 retains its four-blade prop.
Thermal management is one of the most significant technical challenges when using hydrogen as fuel, and a carbon-fiber intake has been added to the rear of the 228’s original nacelle. Additional intakes have been installed on either side of the fuselage just ahead of the wing leading edge to help cool the fuel cell, which sits in the rear cabin.
“We replaced the stock engine with an electrical motor and inverter assembly,” Kiselev says. “It also has cooling radiators and pumps driving coolant through them.”
Modeling predicts some extra drag from the fuselage intakes, he notes, but “the location is not disturbing much of the original airflow, so it should be manageable.”
Ground tests at full power have been conducted on a static rig and began on wing in the last week of June. Once flying, the company expects a test program of around 10 hr. total. Flights involving two hydrogen powerplants on the same aircraft will follow, but those will be on the launch platform, a decision about which has not yet been made public. “It will be one of the Dornier, Twin Otter or Cessna Caravan,” Kiselev says. “They’re all high-wing aircraft and have similar power requirements.”
ATI has provided funding to Zero-Avia under the HyFlyer 1 and 2 programs. CAeS’ Project Fresson also received similar support. ATI awarded a grant to the Blue Bear-led Inception.
But other SMEs attempting to address emission-reduction technology in the same regional segment have not secured similar support.
“Our aircraft is a prototype, but we weren’t allowed to be funded because we didn’t pass the sniff test,” says Neil Cloughley, founder and CEO of Faradair.
Cloughley’s startup is developing an 18-seat regional airliner it calls BEHA (Bio Electric Hybrid Aircraft). ATI funding cannot be allocated to product development. Cloughley argues other companies receiving funding clearly are embarked on programs directly linked to future commercial products. CAeS’ and ZeroAvia’s powertrain prototypes are seen as baselines for retrofit kits, and both have signed letters of intent with operational customers.
“If the rules apply, they should apply to everybody,” Cloughley says. “We’ve been here eight years now, on this journey. We’ve seen companies going down because they were promising the Earth, and it couldn’t be delivered. [Being turned down for funding] is frustrating. But you crack on, and you get on with it.”
Financing the Future
Regardless of whether a company receives grants from the ATI, further vast sums will be required to bring zero-carbon aviation into being. Significant amounts of money from private investors are being pumped into the advanced air mobility sector, yet projects that appear less disruptive can find it difficult to attract venture capital attention.
This is a particular challenge in the UK, where venture capital is in shorter supply compared to the U.S. There may also be a difference between the nations in terms of institutional attitudes toward technology risk.
“We set up this business in 2014. If I’d set it up in America, the aircraft would be flying today,” says Cloughley. “In America, there’s 20 reasons why you can do something and five people prepared to put their hand in their pocket and fund it. Here, there’s 20 reasons why you can’t do something and five companies that will go out of their way to cripple your project.”
Another company with a product that promises near-term emission reductions but which has struggled to attract private capital is Hybrid Air Vehicles (HAV). The business is pursuing the commercial cargo and passenger market for its Airlander 10 hybrid airship. In June, HAV signed a letter of intent with Spanish regional airline Air Nostrum, which intends to operate the airships in 100-passenger configurations on domestic routes by 2026. The companies are expecting carbon reductions of 90% per passenger versus flying the same route on a conventional airliner. HAV says its aircraft offers huge potential to replace its initial hybrid powertrain with hydrogen so it eventually will be a zero-carbon aircraft.
“We find time and time again that the level of risk aversion in the investment community is very high,” says Nick Allman, HAV’s chief operating officer. “We’ve been in this constant battle of needing money to move forward but needing customers to get money, and you need to be moving forward to get customers. At the moment, private investment is very, very difficult in that higher-risk area . . . particularly with a product that’s a bit different.”
Expertise and experience are essential requirements for those tasked with making funding decisions—whether in government, in bodies like the ATI, or in the venture capital arena. But people steeped in the traditions and tenets of “big aerospace” may tend to favor projects that fit in with how aerospace always has functioned.
With zero-emission flight now not just an aspiration but an existential necessity, the old ways of thinking may not always be what are required, Cloughley argues. “We need to look at funding differently, but we have also got to get our heads away from this sort of closed-club mentality,” he says. “It’s not just aerospace—I’ve spoken to startup founders in automotive, in bioscience, everywhere. It’s a real problem across the whole of the UK.”
Infrastructure Conundrum
Investment also is needed in new fuels and the means to move them from the point of manufacture to the aircraft. At Kemble, ZeroAvia has installed the first on-airport hydrogen pipeline in the UK. For its test program, the company is producing hydrogen on site, on a truck provided to the HyFlyer 2 program by the European Marine Energy Center, which runs a hydrogen production plant in the Orkneys.
ZeroAvia has drawn high-pressure hydrogen directly from the truck during ground tests and will begin using the pipeline during flight tests. Kiselev says the pipeline installation process was technically straightforward and partly government-funded, but it required close coordination with the airport, neighboring tenant organizations and insurers.
Installations at major airports will be more complicated and costs higher, but Kiselev believes it should be possible for hubs to fund the entire infrastructure—including on-site production—without external help.
“We calculate that if you have consumption of about half a ton [of hydrogen] a day, it makes sense to do your own installation,” he says. “Then you will be completely independent of any fluctuations in price.”
Hydrogen production on-site at airports may be a necessary feature of zero-carbon aviation, not least because demand for green hydrogen is set to soar. One area where uptake will increase significantly is in producing SAF. The power-to-liquid SAF pathway, which involves capturing CO2 and combining it with hydrogen, remains a relatively immature technology but is, as ATI’s Simon Webb calls it, “the only truly scalable SAF option.”
“The fundamental problem with power-to-liquid SAF is that from an energy point of view, you’re going through the reverse, chemically, of burning it,” Webb says. “When you burn the fuel, you release loads of energy, but the reverse . . . is it takes loads of energy to make it. Compared to today’s kerosene prices per unit of energy, it would cost 4-5 times as much to produce power-to-liquid SAF.”
SAF remains key to many manufacturers’ and operators’ decarbonization plans. This implies hydrogen-powered aircraft may have to compete with SAF-powered aircraft for available hydrogen. But to take that view, says CAeS’ Kavanagh, might be to miss the forest for the trees.
“I don’t necessarily think that the struggle between hydrogen propulsion and hydrogen for SAF is going to be the big competition,” she says. “The big competition will be for everything else—aviation grasping that green hydrogen it needs from all the other industries screaming for hydrogen.”
Securing Skills
Availability of skilled, trained and experienced people is an acknowledged and urgent challenge across the aerospace ecosystem. Aviation emissions may make the sector offputting to new entrants, but decarbonization offers an opportunity to change the narrative.
“We’re in the news every day for the supply chain shortages or aircraft cancellations or sustainability,” says GKN’s Pritchard. “We in aerospace need to be the first choice for people as they go into their [science, technology, engineering and mathematics] courses. I fanatically believe that we’ve got a great story to tell on the sustainability side. We need to engage people in this huge struggle of sustainability. I don’t think we’ve done that as an industry and as a nation yet. We will do that, because we have to.”
Some evidence is emerging that other sectors may be beginning to agree with Pritchard’s analysis. A new name among the exhibitors at Farnborough this year will be Helix—a rebrand announced July 4 for a UK company formerly known as Integral Powertrain.
The company is best known for its eDrive Systems division, set up in 2008, which produces electric motors for supercars. A renewed push into the aerospace sector is being made, not just because management expects that Helix’s technology will be of interest to aviation entities but because the relative maturity of electric powertrains in the automotive sector may be starting to represent a recruitment challenge.
“You could argue that the automotive space is consolidating in terms of architecture, certainly in passenger cars,” says Andrew Cross, Helix’s chief technical officer. “You’re typically seeing permanent magnet machines and single-speed reduction drives and a conventional voltage source, three-phase inverter—technological consolidation. Whereas in aerospace, it’s earlier in the development journey with a lot more change to go. And that’s interesting for young engineers.”
The need to make that case is becoming increasingly urgent because aerospace’s technology trajectory means it now needs to recruit skills that are highly sought in other sectors.
“A hydrogen aircraft still has a motor that turns the propeller and the electrics that feed that, so we’re competing for electrical engineers with the automotive industry,” says CAeS’ Hutton. “We need materials engineers—almost materials scientists—because if you really want to take advantage of 3D printing, you want to know the DNA of all the materials out there and you want to choose the ideal material. They’re the same people that are needed in automotive and other industries. I think aerospace is moving into competition with industries that it didn’t really compete with before.”
“We are actively looking to recruit slightly different skillsets than we would previously have,” Airbus’ Sue Partridge notes. “More chemists would be a tangible example, because the hydrogen story requires us to understand the chemistry, where kerosene was understood years ago. One thing we do really focus on in Airbus—and because we’re a big organization, we’re able to—is early careers: bringing in apprentices and graduates and growing our own.”
“Another area where we’ve had some level of success is bringing people back into the industry who had left,” says Mark Bentall, Airbus UK’s head of research and technology programs. “We’ve been running some specific update programs to bring them back up to speed in the aviation industry and where we are today.”
Bentall acknowledges decarbonization is vital to recruitment and echoes Pritchard’s point that more could be done to explain this side of the industry to the outside world. “[Recruiting new young people] is one of the key reasons why we need to make stronger commitments and shout louder about our sustainability programs.”
A new British OEM?
While approaches and circumstances may differ, there is clear consensus across the UK aerospace sector on the key challenges and a shared sense of positivity that they can be met. One question, however, seems to have divided opinion.
Since the Islander was designed in the early 1960s, the aerospace industry has changed almost beyond recognition. Today’s OEMs are transnational entities, with supply chains that stretch around the globe. Creating a new company capable of competing with Airbus, Boeing and Embraer does not appear feasible.
“We have primes in the UK that are well-placed and, [given] the size of our economy, the UK is well ahead proportionally in aerospace,” ATI’s Webb says. “I think to protect and expand that position is the best use of taxpayers’ money around this new technology. That’s a lower-risk way to do it, and we can still have very high returns by building on what we already have.”
But zero-carbon flight is changing the paradigm once again. Should the UK be looking to get back into the whole-airplane business?
“I believe very strongly that just investing in the subsystem technologies—as the UK has done for the last three or four decades, to keep our place on the supply chain for aircraft manufactured abroad—is really important, but it’s not enough,” says CAeS’ Hutton.
CAeS holds what he describes as “a surprisingly broad and deep range” of approvals and counts almost all the big aerospace OEMs among its client base. Yet even this combination of reputation and capability offers no guarantees of long-term viability.
“Having the world’s biggest aerospace companies coming to us and trusting us is fantastic from a reference point of view, but from a financial forecasting point of view and for the ability to grow your business, it’s rubbish,” Hutton says. “You’re completely at the whim of the discretionary spending of those huge companies. It was great when one of those would do a big project, but if they stopped the project halfway through, it completely killed us.”
CAeS therefore pivoted to act more like an OEM and run its own projects.
“Nobody’s been investing in subregional for decades because the prevailing wisdom was you needed a big airplane to get your cost-per-passenger-mile down,” Hutton says. “But fixed-wing using a runway gives you advantages when you’re trying to get something in the air that is immature technology. That’s why we picked the Islander. It gives us the ability to control our own destiny because we’ve got our own project.”
Over at Duxford Airport, Cloughley has come to a similar set of conclusions. Faradair lacks the approvals CAeS has but has built a base of suppliers who do hold them. Nothing like the BEHA concept—a clean-sheet design based around a triple box wing—is being built anywhere, so Faradair is going to have to build it themselves.
“I started this journey to set up a British aircraft manufacturing company,” Cloughley says. “I wanted to create British jobs. I wanted to put our flag back on the map because we were satisfied with a percentage of programs. We’re better than that. We are well within our rights to say we have earned our battle spurs to have aircraft production again, to start punching our weight out in the market again.”
Others are less convinced. “I think the important thing is that we get to sustainable flight,” says GKN’s Pritchard. “I absolutely believe that the UK can play a significant role in that. But getting it all done in the UK, when you look at how aircraft are produced today globally, that would be one heck of a challenge.”
In other sectors, Hutton points out, the UK has taken steps to insulate itself post-Brexit from issues with global supply chains. In 2017, the government announced funding support for a center to develop batteries for electric cars, eliminating reliance on a critical component not manufactured in-country. Something similar may be necessary for green aviation.
Green aerospace technologies are still in development. The corporate mechanisms required to deliver them commercially are yet to be determined. Perhaps a new UK OEM would not be a top-down, state-created single entity like Airbus but a self-created, bottom-up collaboration between similarly inclined and aligned SMEs.
“If any country should be confident it can build whole aircraft, it should be the UK,” says Hutton. “For some reason we’ve lost the confidence that we can do it. But now we’ve got a window of opportunity to reintroduce whole commercial aircraft manufacturing in the UK in a space that is actually not that worrying to customers for our supply chain business.
“Every industry that’s been disrupted in the last three or four decades has thought they weren’t going to be the one that was going to be disrupted next,” Hutton notes. “And that’s exactly what’s happening here. And I don’t think people get it.
“We’ve gotten so comfortable just putting our money into technologies. Whenever you challenge the UK to put funding into the whole-aircraft side, you just get that slight: ‘Well, we’re never going to do that,’” he says.
“I think, really? Is that something that was true five years ago because the only way to enter the market in a commercially viable space was in single-aisle or twin-aisle [production] where there’s far too much competition—or have people not [yet] realized the world has changed?”
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