The UK aerospace sector has published a first-of-its-kind Non-CO2 Technologies Roadmap that sets out a collective ambition to improve understanding of non-CO2 aircraft emissions and the technology advancements needed to address their climate impact. Non-CO2 emissions from aviation are considered to contribute a climate impact in terms of global warming but there remains a high level of scientific uncertainty as to the quantified impacts. Developed with input from almost 100 leading experts from industry and academia, the roadmap aims to reduce this uncertainty and deliver technology solutions to mitigate or prevent non-CO2 emissions during flight. The roadmap will also inform the activities to be prioritised for funding under a new non-CO2 programme managed by the Aerospace Technology Institute, UK Department for Business and Trade and Innovate UK. Meanwhile, in the US, engine manufacturer Pratt & Whitney has joined a FAA ASCENT project to study non-CO2 emissions from ground testing of conventional jet fuel and 100% sustainable aviation fuel.

Collectively, non-CO2 emissions refers to the direct and indirect effects of combustion found in aircraft exhaust plumes, aside from carbon dioxide, which research suggests could be greater than the impact of CO2 alone. The climate impact from aviation emissions at high altitude, such as the formation of contrails, is highly complex and variable. In addition, there are complex interactions and interdependencies between emission types, as well as variation in the persistence and length of time that different emissions impact the climate. Contrails, for example, can have cooling as well as warming effects.

Aircraft emissions and their climate interactions (© ATI)

The new funding programme aims at accelerating the research and development of technologies related to reducing these broader emissions. The ATI Non-CO2 Programme and the funding will support the UK government’s Jet Zero Strategy and its commitment to tackle aviation’s non-CO2 emissions.

The Non-CO2 Technologies Roadmap becomes the fourth pillar of the UK Aerospace Technology Strategy, ‘Destination Zero’, which guides industry and government investment into aircraft technologies, with the aim of “growing the UK’s share of the global aerospace market, supporting high-skilled jobs and leading the way on more sustainable air travel.”

Delivered in partnership with the UK Department for Business and Trade and Innovate UK, the ATI Non-CO2 Programme will focus predominantly on industrial research and technology development or enabling-technology projects. It will bring academia, government institutions and industry together to translate theoretical concepts into viable technologies. A new Expert Advisory Group is being created to bring industrial and scientific expertise to the programme.

“While reducing and eliminating carbon emissions rightly remains a key focus for aviation globally, advanced technologies being developed today should also consider broader atmospheric emissions,” said Gary Elliott, CEO of the Aerospace Technology Institute.

“As understanding of aviation’s non-CO2 impact grows, so too does the market opportunity and the UK is ideally positioned to unlock the technologies that will maintain global connectivity while meeting environmental commitments and delivering economic benefit across the UK.”

The Non-CO2 Programme will be funded through the ATI Programme, which, since its launch in 2014, has invested £3.6 billion ($4.5bn) of joint government and industry funding in aerospace technology R&D. ATI says up to £17 million over four years will be allocated to successful projects. The grant funding can be applied for during a two-week application process starting 13 May 2024, with the outcome expected by 18 June. Potential applicants can also join a webinar to hear more about the roadmap and programme on 18 April.

UK Industry Minister Nusrat Ghani commented: “I am delighted to see our world-leading aerospace sector propelling research and development  to new heights of innovation in the pursuit of cleaner, greener air travel. This roadmap and programme will harness the world-class capabilities of UK industry and academia as they work together at the forefront of technological innovation to address globally significant challenges.”

(Clearer version of roadmap here)

In the United States, aerospace industry and academia are also working together to help understand and reduce the climate impact from aviation’s non-CO2 emissions. A project conducted under the FAA’s ASCENT programme by Pratt & Whitney, Missouri University of Science and Technology (Missouri S&T), Aerodyne Research and the Environmental Protection Agency will measure emissions from a Pratt &Whitney GTF engine combustor rig test stand using conventional Jet A kerosene and 100% sustainable aviation fuel.

The project will compare emissions from Jet A and SAF comprised of 100% HEFA-SPK supplied by World Energy. The rig tests will take place at Pratt & Whitney’s Middletown facility in Connecticut, using a Rich-Quench-Lean combustor. According to the engine manufacturer, the rig allows testing of the full range of combustor operating conditions, including at take-off, ground and cruise altitudes, to help better understand the environmental and emissions benefits of using SAF. The partners will collaborate on test design, execution and emissions data analysis.

“As the aviation industry targets a goal of net zero CO2 emissions by 2050, we continue to pay close attention to addressing the environmental impact of other emissions, including cruise non-volatile particulate matter and NOx,” said Sean Bradshaw, senior technical fellow of sustainable propulsion at Pratt & Whitney. “Combustor rig tests with 100% SAF provide a controlled environment for generating valuable baseline data, which will support future studies using full-scale engines on-wing at ground and flight test conditions.”

Added Dr Philip Whitefield of Missouri S&T: “SAF containing low sulphur and aromatic hydrocarbon concentrations could contribute to reduced sulphur dioxide and non-volatile particulate emissions, which are associated with contrail formation and the impact to global warming.”

Christopher Surgenor

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In what ICAO Council President Salvatore Sciacchitano described as the UN civil aviation agency’s most important event of the year, countries are convening this week in Dubai to agree a global framework on a cleaner energy future for aviation. The purpose of the Conference on Aviation Alternative Fuels (CAAF/3) is to steer policy direction and financing to aid the rapid shift towards new forms of sustainable energy, in particular sustainable aviation fuels, to meet ICAO’s Long Term Aspirational Goal (LTAG) of net zero carbon emissions from international aviation by 2050. Sciacchitano said it would be a massive task that required immediate collective action. SAF production remains largely confined to Europe and the USA but the collective global target will require huge support and investment for energy transition in the developing world. The week-long meeting has been marked with an Emirates A380 demonstration flight with one engine powered by 100% SAF.

“We must urgently scale up the development and deployment of sustainable, lower carbon and other clean energy aviation fuels in order to meet the sustainability expectations of both the world and the stakeholders,” said Sciacchitano in his opening address at CAAF/3. “We have a massive task ahead of us this week as we deliberate on the ICAO Global Framework for aviation’s cleaner energy transition, a key step for the sustainable development of air transport. ICAO’s main priority is the implementation and achievement of LTAG. To do this, we need to take collective action now and CAAF/3 can be instrumental in laying the building blocks in terms of policy and planning, regulatory framework adjustments, implementation support and financing.

“This is also an opportunity for States to demonstrate strong leadership in addressing international aviation emissions just before the UN’s COP28 climate change conference also taking place here in the UAE. A successful, robust and ambitious global framework can only serve to shine a bright spotlight on the shared efforts and commitment to decarbonising our sector. We have a great opportunity to show and communicate to the world that aviation is seriously and strongly committed to decarbonise by 2050.”

In a video address, UN Secretary-General Antonio Guterres said aviation was one of the most challenging sectors to decarbonise, “but with innovation and investment, it can be done.”

He added: “A net-zero aviation sector means cleaner energy sources on a global scale. It means economic policies and regulations that can support a just and equitable transition while attracting investors, and it means measures such as carbon pricing, low-carbon fuel standards and subsidies for sustainable aviation fuels. The global framework emerging from this conference is a critical step towards a clean and prosperous future for this vital sector. By moving at jet speed you can speed up the clean energy revolution our world needs.

“With the upcoming COP28, now is the time to turn ambition into concrete action to find ways to deliver on your net zero target and shape a better, cleaner future for all.”

CAAF meetings take place only on a six-year basis, the first held in Brazil in 2009, and CAAF/3 is the culmination of a series of stocktaking and pre-CAAF/3 conferences and consultations to prepare the ground for a ‘2050 ICAO Vision’ for SAF, lower carbon aviation fuels (LCAF) and other aviation cleaner energy sources in order to define a global framework in line with ICAO’s ‘No Country Left Behind’ initiative that takes into account national circumstances and capabilities. SAF, LCAF and other aviation cleaner energies are expected to make the largest contribution towards achieving the LTAG.

The 2050 Vision acknowledges that no single fuel source will be produced at a level necessary to achieve the LTAG and so the framework needs to be flexible and not exclude any particular fuel source, pathway, feedstock or technology that meets the CORSIA eligible fuels criteria, says ICAO.

Since earlier this year, a Small Group for Preparations for CAAF/3, under the Climate and Environment Committee (CEC) of ICAO’s governing Council, has been considering possible CAAF/3 outcomes, including a draft global framework. The framework is built across four interconnected building blocks that need to advance and work together: policy and planning; regulatory frameworks; implementation support; and financing.

Although there has been general convergence on the Vision, some differences remain around aviation cleaner energies and financing, which will be discussed during the conference.

A number of States want to see CAAF/3 emerge with a quantified goal in order to send a political signal of support for sustainable fuels that could unlock private sector investment around the world.

“The reason why investors need this outcome is that it is crucial to assuring the durability of their investments,” US government representative Annie Petsonk said during an opening panel session. “If they are going to make the major investments that allow SAF to be produced in refineries and to develop the required feedstocks and supply chains, they want to see governments are serious about this transition. Through informal consultations I have had already, I am very hopeful that I will be able to communicate a positive outcome to them.”

The US is also supporting the creation of the ICAO Finvest Hub, which aims to act as a facilitating platform to connect projects contributing to the decarbonisation of international aviation, including feedstock and SAF production, with potential public and private investors. A priority of the initiative would be to support developing countries and those with special needs in financing aviation decarbonisation projects. It would also offer technical assistance, capacity building and guidance on the development of legal and policy frameworks.

Industry is also represented at CAAF/3 and has a similar wish list. “There are two key outcomes we would like to see from the conference: a goal for SAF deployment that can provide investment certainty to the finance markets and influence policy actions around the world, and a supportive global framework that will ensure countries everywhere can take advantage of the opportunities to build new energy industries and secure jobs in supplying SAF,” said Haldane Dodd, Executive Director of the cross-industry Air Transport Action Group (ATAG).

ATAG says the transition to SAF is already underway, with policy measures being implemented or discussed in around 40 countries, with $45 billion in forward SAF purchase agreements in place with airlines, operators and corporate partners. Ten facilities are currently producing SAF, it says, but by 2029 over 150 projects in 35 countries are being explored that could be used for SAF production.

“The SAF scale-up has begun,” said Dodd. “Over 10 times more SAF was delivered to airlines in 2022 than in 2019. That pace of development will continue but needs to accelerate significantly to keep in line with the industry’s path to net zero.

“Three things are needed to make the aviation energy transition happen: government policy to support supply and create certainty for demand; financing of the potentially $1.5 trillion in infrastructure capital needed to supply SAF at the scale required; and a serious effort by the traditional energy sector to shift their products from fossil to sustainable fuels. We believe the CAAF/3 meeting can set the scene for these developments and help catalyse the transition in aviation. These are tough decisions and complex challenges, but necessary ones to progress as climate change makes its impacts felt.

“A global framework from CAAF/3 will help capacity building and access to finance so that countries everywhere can build SAF industries of their own. Enormous value can be created in diversifying and democratising energy supply if governments grasp the opportunities ahead of them.”

Added Laurent Donceel, Deputy Managing Director of Airlines for Europe (A4E): “The future of aviation depends on sustainable aviation fuels and it is critical the CAAF/3 meeting produces a global agreement for a net-zero aviation with realistic targets to promote the use of SAF. Global investments in SAF and boosting the energy transition in aviation will create a bounty of jobs and growth around the world.

“Europe and the USA are accelerating down the runway towards a more sustainable future so it’s critically important that the rest of the world keeps up and delivers a truly net zero aviation industry. CAAF/3 is an ideal opportunity to set this in stone.”

Environmental NGOs belonging to the International Coalition on Sustainable Aviation have called on the meeting “to adopt a global aspirational quantified objective for 2050 and an aspirational trajectory that are consistent with the Paris Agreement temperature goals, and that prioritise the environmental and social integrity of alternative fuels.”

Setting the goal, they say, requires adopting, primarily, a metric that focuses on the carbon intensity of alternative fuels on a lifecycle basis, consistent with CORSIA eligible fuels methodology.

“A successful outcome requires focusing on defining an ambitious vision that prioritises the environmental and social integrity of alternative fuels and therefore avoids trading an environmental threat for another,” said a statement presented at CAAF/3. “The focus should always be on quality rather than quantity.”

In addition to a robust sustainability standard, said the NGOs, CAAF/3 should emphasise transparency to ensure alternative fuels are accurately reported and accounted for, with the avoidance of double counting critical for integrity.

The statement notes that whereas the CAAF/2 vision focused solely on sustainable aviation fuels, the scope for CAAF/3 has been expanded to cover not only other cleaner energy sources such as cryogenic hydrogen and electricity, but also lower carbon aviation fuels (LCAF) of fossil origin.

“ICSA believes that while LCAF may have potentially lower carbon emissions on a lifecycle basis, all fuels of fossil origin must, by definition, be regarded as unsustainable. The CAAF/3 Vision should avoid the use of encompassing terms such as ‘sustainable fuels’ and instead use suitable terms such as ‘alternative fuels’.

To coincide with CAAF/3, Emirates this week has become the first airline to operate an A380 demonstration flight using 100% SAF. In a collaboration with Airbus, Engine Alliance, Pratt & Whitney, ENOC, Neste and Virent, the Emirates aircraft took off from Dubai International Airport with one of its four engines powered on 100% SAF. The flight carried four tonnes of SAF, comprised of HEFA-SPK provided by Neste and HDO-SAK (hydro deoxygenated synthetic aromatic kerosene) from Virent. ENOC helped to secure the neat SAF comprised of HEFA-SPK and blended it with SAK at its facility in the airport.

The 100% SAF was used in one Engine Alliance GP7200 engine, while conventional jet fuel was used in the other three engines. The PW980 auxiliary power unit from Pratt & Whitney Canada also ran on 100% SAF. The flight on November 22 was preceded by robust engine testing, with the objective of validating the engine’s capability to run on the specially blended 100% drop-in SAF without affecting its performance or requiring modifications. Ground engine testing took place at the Emirates Engineering Centre in Dubai.

Earlier this year, Emirates completed the first 100% SAF-powered demonstration flight in the region on a GE90-powered Boeing 777-300ER. Shell has supplied Emirates with 315,000 gallons of blended SAF for use at Dubai and the airline currently uplifts SAF in Norway and France. Emirates recently expanded its partnership with Neste for the supply of over 3 million gallons of blended SAF in 2024 and 2025 for flights departing from Amsterdam Schiphol and Singapore Changi airports.

“The growing global demand for lower-emission jet fuel alternatives is there, and the work of producers and suppliers to commercialise SAF and make it available will be critical in the coming years to help Emirates and the wider industry advance our path to lower carbon emissions,” commented Adel Al Redha, COO, Emirates Airline.

Videos of the CAAF/3 proceedings are available on ICAO TV

Top photo: ICAO Council President Salvatore Sciacchitano addresses CAAF/3

Emirates A380 100% SAF demonstration flight:

Christopher Surgenor

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Boeing has selected engine maker Pratt & Whitney and its sibling company Collins Aerospace as partners in its groundbreaking X-66A sustainable aircraft programme, in which a former passenger jet will be converted to test the airframer’s futuristic Transonic Truss-Braced Wing (TTBW). The transformation of the 1995-built MD-90 twinjet is part of NASA’s Sustainable Flight Demonstrator Project, which is tasked with trialling a range of new technologies to increase aircraft efficiency and reduce carbon emissions. In a radical retrofit, Boeing will remove the plane’s low, rear-swept wings and instal high-mounted, long, thin wings, supported by diagonal trusses. The new, forward-swept wings are designed to reduce aerodynamic drag, improving fuel efficiency by up to 10%, while the addition of Pratt & Whitney’s GTF (geared turbofan) engines, and new nacelles and engine accessories from Collins, together with other initiatives, could improve total efficiency by as much as 30%. Both companies, part of the RTX aerospace group, will also support ground and flight tests of the experimental plane, which are scheduled to commence in 2028.    

The Transonic Truss-Braced Wing programme is a key element of broader US efforts to decarbonise emissions from commercial aircraft, and will help inform the design of future narrowbody airliners. The former Delta Airlines MD-90 to be used in the programme recently flew from Victorville, California, where it was stored, to nearby Palmdale for modification.

NASA estimates that single-aisle airliners generate more than 50% of global emissions from aircraft, but says technical and economic risks often prevent promising technologies from proceeding to production. It is partnering with the aerospace industry on the X-66A programme to help develop and flight test an advanced airframe and new technologies to improve fuel efficiency while reducing emissions, and to gather ground and flight test data to validate the outcomes.

“We are excited to be working with Boeing on the X-66A Sustainable Flight Demonstrator, making critical contributions to accelerate aviation towards its 2050 net-zero greenhouse gas emission goal,” said Ed Waggoner, Deputy Associate Administrator for Programs in the NASA Aeronautics Research Mission Directorate.

The agency said the research results would help the aerospace industry to progress development of next-generation single-aisle aircraft which meet the goals of the US Aviation Climate Action Plan.   

“This marks an important step in the Sustainable Flight Demonstrator project, advances Boeing’s commitment to sustainability and brings us closer to testing and validating the TTBW design,” said Dr Todd Citron, Boeing’s Chief Technology Officer.

“The X-66A is NASA’s first experimental plane focused on helping the US achieve its goal of net-zero aviation greenhouse gas emissions,” he said. “The learnings from the Sustainable Flight Demonstrator and the partnership with NASA are important elements in the industry’s efforts to decarbonise aviation. We’re grateful for the support from RTX on this critical effort.”  

Geoff Hunt, Pratt & Whitney’s SVP Engineering and Technology, said NASA’s Sustainable Flight Demonstrator programme highlighted how collaboration across the aerospace sector could help expedite the transition to net zero emission flight.

“We’ll work with Boeing to apply GTF engines to the X-66A and help demonstrate the potential of its pioneering truss-braced wing design,” he said. Pratt & Whitney’s geared fan engines, introduced into service in 2016, are designed to offer up to 20% better fuel efficiency than conventional powerplants and certified to operate with sustainable aviation fuel.

Further improving the efficiency of the testbed aircraft will be lightweight engine nacelles, produced by Collins using durable composite and metallic materials. It will also provide control system components for the GTF engines to be used on the testbed aircraft, including their heat exchangers, integrated fuel pump and starter, and air turbine starter and electronic controls.

“Collins has as long history of successful partnerships with NASA, Boeing and Pratt & Whitney, with decades of experience pushing the boundaries of innovation in aerospace,” said the company’s SVP Engineering and Technology, Dr Mauro Atalla. “Now, as part of the Sustainable Flight Demonstrator programme, we will work together to demonstrate new technologies and systems to support the next generation of low-emission single-aisle aircraft that will play an integral role in reducing the environmental footprint of the aviation industry.”    

RTX is also collaborating with NASA on other sustainable aviation projects, including Hybrid Thermally Efficient Core (HyTEC) and Hi-Rate Composite Aircraft Manufacturing (HiCAM), as well as progressing its engines to operate with 100% unblended SAF, hybrid-electric power and hydrogen fuel.

Image (Boeing): A render of the X-66A

Tony Harrington

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The unprecedented heatwave sweeping the UK during the 2022 Farnborough International Airshow was a timely, if unwelcome, prod to the aviation sector that it must continue raising its game in the collective fight to mitigate the growing impact of global warming. Established and emerging aerospace players, from Airbus to ZeroAvia, used the biggest air show since the start of the pandemic to promote and progress deals, partnerships and initiatives designed to help deliver net zero emissions by 2050. In addition to more than 300 orders for new-technology aircraft, Farnborough showcased a range of developments on new propulsion systems and fuels, the growing trend to convert fossil-fuelled aircraft to zero emission power and continued strong growth in the urban air mobility sector, reports Tony Harrington. As countries met in Montreal to discuss a long-term target to reduce emissions from international aviation, the UK government released at the air show its eagerly-awaited Jet Zero Strategy to decarbonise the British aviation sector.

Having recently unveiled plans to use an A380 superjumbo as a testbed for its ZEROe hydrogen propulsion programme, Airbus announced it would convert a second A380, this time to be used in a collaboration with engine manufacturer CFM International to test new open-architecture powerplants. This engine technology, known as RISE (Revolutionary Innovation for Sustainable Engines), features large external fans which are expected to drive significant operating efficiencies and cut emissions by 20%.

Airbus UpNext, a subsidiary of the airframer, also announced a partnership with the German Aerospace Center (DLR) to study contrails created by hydrogen-powered engines. Through a new project called Blue Condor, two modified Arcus gliders will be deployed, one powered by a conventional kerosene combustion engine, the other hydrogen combustion. A chase aircraft will follow each of these craft to assess and compare their contrails at high altitude, in what will be the first in-flight tests by Airbus using a hydrogen engine.

To further support its hydrogen ambitions, Airbus has invested an undisclosed amount in Hy24, described as the world’s largest clean hydrogen infrastructure investment fund, focused on supporting large-scale green hydrogen infrastructure projects. “Since 2020, Airbus has partnered with numerous airlines, airports, energy providers and industry partners to develop a stepped approach to global hydrogen availability,” said Karine Guenan, VP ZEROe Ecosystem, Airbus. “Joining a fund of this magnitude demonstrates Airbus’ continuously active role in infrastructure investments for the production, storage and distribution of clean hydrogen worldwide.” 

Rolls-Royce and European low-cost airline easyJet also announced a hydrogen propulsion programme, the H2Zero Partnership, to jointly pioneer the development of hydrogen combustion engine technology suitable for a range of aircraft, including narrowbody airliners, from the mid-2030s. This collaboration, which combines Rolls-Royce’s engine expertise and easyJet’s operational experience, will start later this year with engine tests on the ground and ambitions by both companies to also progress to flight tests.

“In order to achieve net zero by 2050, we have always said that radical action is needed to address aviation’s climate impact,” said Johan Lundgren, CEO of easyJet. “The technology that emerges from this programme has the potential to power easyJet-size aircraft, which is why we will also be making a multi-million-pound investment into this programme. In order to achieve decarbonisation at scale, progress on the development of zero-emission technology for narrowbody aircraft is crucial. Together with Rolls-Royce, we look forward to leading the industry to tackle this challenge head-on.”

Boeing, which announced more than 200 aircraft orders at the show, has become a founding member of the University of Sheffield Energy Innovation Centre to explore various methods of producing sustainable aviation fuel, and bringing it to market. During the air show, the aircraft OEM revealed it was advancing its partnership with the University of Cambridge on the Aviation Impact Accelerator (AIA), an international group of practitioners and academics convened by the university. AIA develops interactive evidence-based models, simulations and visualisation tools for decision-makers and the wider engaged public to understand the pathways to net zero flight. The outcomes and key learnings will eventually be integrated into Boeing’s Cascade data modelling tool, which provides real-time visualisation of carbon emission reductions in aviation, and also announced during the show. The model assesses the full lifecycle impacts of renewable energy by accounting for the emissions required to produce, distribute and use alternative energy carriers such as hydrogen, electricity and SAF. Boeing said it plans to utilise the tool with airline operators, industry partners and policymakers to inform when, where and how different fuel sources intersect with new airplane designs.

The company also expanded a long-standing collaboration with Japan’s Mitsubishi Heavy industries to study electric and hydrogen propulsion, development of green hydrogen, new feedstocks and technologies for development of SAF, carbon capture and conversion, sustainable materials and new aircraft design concepts. As well, Boeing announced a $50 million investment in AEI HorizonX, a partnership it established with private equity group AE Industrial Partners to support transformative aerospace technologies.

“In order for the aviation industry to meet its net zero carbon emissions commitment by 2050 it will take all of us collaborating and investing in scientific research and testing,” said Boeing’s VP of Global Sustainability Policy, Brian Moran.

Boeing also announced a new partnership with Alder Fuels to expand production of SAF around the world. Using Boeing aircraft, the companies will test and qualify Alder-derived SAF, advance policies to expedite aviation’s energy transition.

Meanwhile, Virgin Atlantic, Corendon Dutch Airlines and Albawings have selected Boeing’s Jeppesen FliteDeck Advisor to optimise operational efficiency and reduce fuel consumption across their fleets of Boeing aircraft. During a three-month trial on its 787 Dreamliners, Virgin Atlantic found the digital solution delivered cruise fuel savings of 1.7%, saving around 1,900kg of CO2 per flight.

Hydrogen propulsion pioneer ZeroAvia secured an additional $30 million from new investors including Barclays Sustainable Impact Capital, NEOM, a sustainable regional development in Saudi Arabia, and the impact technology fund AENU, as well as additional capital from International Airlines Group, an existing investor and parent of airlines including British Airways, Iberia, Aer Lingus, Vueling and LEVEL. “Our new investors are each looking at our journey through a different lens,” said Val Miftakhov, founder and CEO of ZeroAvia, “but all energised by our mission to enable zero-emission flight using hydrogen-electric engines.”

ZeroAvia, Universal Hydrogen and Ampaire announced during the air show a total of 55 firm orders for kits to convert commuter or turboprop aircraft from fossil fuels to zero-emission electric or hydrogen propulsion, while Swiss aero-battery manufacturer H55 launched a partnership with Canadian training group CAE and Piper Aircraft to convert to battery-electric power two-thirds of CAE’s fleet of Piper Archer training aircraft. Ampaire also flagged in excess of 200 orders on the horizon for its Eco Caravan and Eco Otter aircraft, re-engined variants of the Cessna Caravan and De Havilland Twin Otter regional aircraft.

GKN Aerospace revealed during the show that advances in fuel cell technology could enable hydrogen-electric propulsion to be scaled up more quickly than previously thought. The company had assumed that hydrogen propulsion was easiest to introduce for aircraft seating around 19 passengers, but now believes the use of cryogenic cooling technology can expedite deployment of the technology to power aircraft seating 96 or even more passengers, and reducing both CO2 and non-CO2 emissions.

Norway’s Widerøe Zero, the sustainability arm of regional airline Widerøe, signed a MoU with Embraer to help develop the airframer’s new Energia family of zero emission aircraft, with four variants ranging from 19 to 50 seats, while Collins Aerospace has completed the preliminary design of a 1-megawatt motor and controller to power a hybrid-electric demonstrator aircraft for the engine manufacturer Pratt & Whitney Canada.

Collins and Pratt & Whitney also launched a new electric propulsion concept, the Scaleable Turboelectric Powertrain Technology demonstrator (STEP-tech), to power novel aircraft including high-speed electric vertical take-off or landing craft (eVTOL), unmanned aerial vehicles (UAV) and small-to-medium commercial aircraft, while new deals, developments and partnerships were announced in the eVTOL segment by companies including Germany’s Lilium, Embraer’s Eve, UK-based Vertical Aerospace, French start-up Ascendance Flight Technologies and a tie up between Rolls Royce and Hyundai Motor Group’s air taxi division, Supernal.

GE Aviation announced a milestone for its own electric engine programme, conducting the world’s first test of a hybrid-electric propulsion system in simulated high-altitude conditions. Using NASA’s Electric Aircraft Testbed (NEAT) in Sandusky, Ohio, GE assessed a pair of hybrid electric systems, one to simulate an aircraft’s left engine, the other its right engine, in conditions expected when flying at 45,000 feet. The test simulated the electrical loads needed to optimise engine performance, while propelling and powering an aircraft at that altitude.   

Mohamed Ali, VP and GM of Engineering for GE Aerospace, said: “We’re making aviation history by developing the technology to help make hybrid electric flight possible for everyday commercial air travel. We just passed a key milestone by successfully concluding the world’s first test of a high power, high voltage electric system at altitude conditions. This is one of many milestones in our journey with NASA towards demonstrating a hybrid electric aircraft engine system for a more sustainable future of flight.”

A small Spanish airline, AlbaStar, was identified at Farnborough as the European launch customer for the US-made WheelTug electric taxiing system, which enables aircraft to be manoeuvred around airports without using external tractors or their own engines. Using a small electric motor installed within the nosewheel, pilots can control all ground movements by their aircraft, including reversing from airport aerobridges. AlbaStar, which operates six Boeing 737 jets, estimates that in a year the WheelTug system could eliminate 1 million kilograms of CO2 and nitrogen oxide emissions from the airline’s operations. The WheelTug system is due to be introduced into service in mid-2023.

Image (Embraer): Norwegian airline Widerøe has signed a MoU with Embraer to help develop the airframer’s new Energia family of zero emission aircraft

Boeing will source two million gallons (7.5 million litres) of sustainable aviation fuel from Texas-based Epic Fuels in what the companies have described as “the largest announced SAF procurement by an airframer”. Throughout 2022, Boeing will use the SAF in its commercial operations in both Washington state and South Carolina to help fuel the test, ferry and customer flights of new aircraft, as well as operations by its giant Dreamlifter freighters that are used to transport major aircraft components and other large shipments, reports Tony Harrington. Use of the fuels will progress Boeing’s commitment that by 2030 it will offer commercial aircraft which are both able and certified to fly using 100% SAF, and also support broader initiatives by the aerospace industry to grow SAF use. In other OEM developments, European turboprop manufacturer ATR has test flown an ATR 72-600 aircraft with one of its two engines fuelled by 100% SAF, while regional jet maker Embraer is planning a similar trial in partnership with engine manufacturer Pratt & Whitney.

The latest purchase agreement between long-term partners Boeing and Epic Fuels will include supplies developed from inedible agricultural waste, which will then be used to produce a blend of 30% SAF and 70% conventional jet fuel. Epic will also continue to provide customised blends graduating from 50 to 100% SAF for use in the Boeing ecoDemonstrator programme, in which new technologies are assessed on flights by testbed aircraft. Although the maximum SAF-fossil fuel blend approved by regulators is 50/50 for commercial flights, Boeing, alongside other airframe and engine manufacturers, is working to achieve universal approval for 100% SAF use to power everyday flights.

“SAF is a safe, proven, immediate solution that will help achieve our industry’s long-term commitment to net zero carbon emissions by 2050,” said Sheila Remes, Boeing VP Environmental Sustainability. “Boeing has been a pioneer in making sustainable aviation fuels a reality. Through this agreement we will reduce our carbon footprint and have SAF available for customer deliveries as well as our own operations.” 

The company began test flights with SAF in 2008, and in 2011 helped achieve regulatory approval to use the fuels on commercial flights. In 2018, through its ecoDemonstrator programme, Boeing used a FedEx B777 freighter to perform the first test flight of a commercial aircraft using 100% SAF, and in 2019 started offering airlines the option to use SAF on delivery flights of new aircraft. The latest fuel purchase will support Boeing’s commercial operations in Everett, Renton and Seattle, in Washington state, and in North Charleston, South Carolina.

“Epic and Boeing have been partners for decades. Working together, we are making sustainability more attainable for our customers,” said Kyle O’Leary, Vice President and COO of Epic Fuels, an independent supplier with primary operations in the US and Canada. Epic has partnered with Boeing to test alternative fuels on Boeing 757 and 787 testbed aircraft, and with Alaska Airlines, first in a trial of biofuel produced from non-edible, sustainable corn, and later the first commercial flight using renewable alternative jet fuel produced from residual forest waste.  

In Europe, ATR Regional Aircraft has just achieved seven hours of ground and flight testing of an ATR 72-600 prototype aircraft, on which one of the two engines was powered by 100% sustainable aviation fuel produced from renewable waste and residues raw material such as used cooking oil. The tests were conducted with Finnish waste-to-SAF producer Neste and Swedish ATR operator Braathens Regional Airlines, as part of a collaboration to achieve certification of ATR aircraft to use 100% SAF by 2025.  The three companies are planning to operate a SAF demonstration flight with a Braathens aircraft later this year.

“The achievement of this great milestone shows that we are fully committed to making the use of 100% SAF possible and helping our customers meet their objectives to provide even more sustainable air links, not in 2035 or 2050, but in the coming years,” said Stefan Bortoli, ATR’s CEO. The company has estimated that with 100% SAF in both engines, CO2 emissions from an ATR aircraft flying on a typical regional route would be reduced by 82%.

Regional jet manufacturer Embraer and engine manufacturer Pratt & Whitney have also announced plans to operate a demonstration flight this year using 100% SAF. The flight will be operated with an Embraer E195-E2 aircraft powered by Pratt and Whitney GTF engines. “Collaboration is an essential pre-requisite for our industry to achieve our environmental goals,” said Arjan Meijer, CEO of Embraer Commercial Aviation.

GE Aviation and Emirates have also signed a Memorandum of Understanding to conduct a 100% SAF test flight by the end of this year, using an Emirates Boeing 777-300ER powered by GE90 engines.  

Photo: Boeing