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

Just 18 months after Airbus declared its ambition to bring a zero-emissions aircraft into service by 2035, a critical development in that timeline has taken place around the engine that could take this aircraft to the air, reports Mark Pilling. In a transatlantic press conference, Airbus announced the signing of a partnership agreement with CFM International, a 50/50 joint venture between the engine giants GE and Safran Aircraft Engines, to collaborate on a hydrogen engine demonstration programme that will take flight around the middle of this decade. The programme’s objective is to perform ground and flight tests on a direct combustion engine fuelled by hydrogen, in preparation for entry-into-service of a zero-emission aircraft by 2035. The demonstration will use the very first Airbus A380 – MSN 1 – as a flying testbed equipped with liquid hydrogen tanks prepared at Airbus facilities in France and Germany. Airbus will also define the hydrogen propulsion system requirements, oversee flight testing and provide the A380 platform to test the hydrogen combustion engine in cruise phase, as well as measure condensation trails.

Under the ZEROe demonstrator programme, CFM will modify the combustor, fuel system and control system of a GE Passport turbofan to run on hydrogen. The engine, which is assembled in the US, was selected because of its physical size, advanced turbo machinery and fuel flow capability. It will be mounted along the rear fuselage of the flying testbed on a stub support to allow engine emissions, including contrails, to be monitored separately from those of the engines powering the aircraft. CFM will undertake an extensive ground test programme ahead of the A380 flight test.

The A380 will be fitted with four hermetically-sealed liquid hydrogen fuel tanks in the rear of the fuselage delivered from the Airbus Zero Emissions Development Centres, which are working on metallic hydrogen tanks, said Sabine Klauke, Chief Technical Officer at Airbus. The fuel load will consist of 400kg of liquid hydrogen. A new cryogenic fuel distribution system, including a new pump, seals and pipes will be required for this engine with the liquid hydrogen converted into a gas before combustion. There will also be cockpit modifications to monitor and manage the propulsion system.

“This is the most significant step undertaken at Airbus to usher in a new era of hydrogen-powered flight since the unveiling of our ZEROe concepts back in September 2020,” said Klauke. “By leveraging the expertise of American and European engine manufacturers to make progress on hydrogen combustion technology, this international partnership sends a clear message that our industry is committed to making zero-emission flight a reality.”

“Hydrogen combustion capability is one of the foundational technologies we are developing and maturing as part of the CFM RISE Program,” said Gaël Méheust, CEO of CFM. “Bringing together the collective capabilities and experience of CFM, our parent companies and Airbus, we really do have the dream team in place to successfully demonstrate a hydrogen propulsion system. We are deeply committed to helping the industry achieve the industry’s net carbon emissions goal that we have collectively set for ourselves through the Air Transport Action Group declaration last October. To achieve this goal, the industry needs to take action now – and we are.”

GE and Safran launched the technology demonstration programme RISE – Revolutionary Innovation for Sustainable Engines – in June 2021. It is aimed at developing open rotor powerplants that can be powered by 100% sustainable aviation fuel or liquid hydrogen for the next generation of single-aisle aircraft from 2035.

“Achieving sustainable aviation growth requires a holistic industry-wide approach. From the CFM perspective, we certainly support the broader use of sustainable aviation fuels – something the industry can do today to have a huge impact on its carbon footprint. Of course, this is in addition to building ever more fuel-efficient aircraft engines,” said Méheust.

“However, it is not the goal of our industry just to lower its carbon footprint, it is net zero carbon emissions and to achieve this we need to explore all the technology pathways at our disposal and hydrogen propulsion brings great promise. It is the true zero carbon emissions solution and at CFM it is one of the fundamental technologies we are developing and maturing as part of the RISE programme.”

Mohamed Ali, VP Engineering at GE Aviation, added: “CFM is now working with Airbus to make zero-emission aircraft a step closer to reality. Both GE and Safran, as parent companies of CFM, have experience with hydrogen fuel to power land-based gas turbines and rockets. This experience makes CFM the best-positioned engine maker to join the Airbus ZEROe programme.”

Explaining the challenges of hydrogen aircraft propulsion, he said: “For aircraft engine propulsion, to distribute the fuel from the storage tanks to the engine combustor, it will require the development of a new cryogenic fuel delivery system. Before the liquid hydrogen can enter the engine’s combustion chamber, we will need to convert it into gas to be burnt cleanly in the combustor. Unlike jet fuel, hydrogen is injected into the combustor as gas, so making its mixing with air actually easier. “

However, hydrogen burns at a much higher temperature than jet fuel, so CFM will need to build on its experience with advanced materials, coatings and cooling technology to develop combustor and turbine parts to withstand that temperature, and still achieve the same or better durability than what we have today, he said.  Burning at a higher temperature also makes hydrogen susceptible to other emissions like nitrogen oxides and burns ten times faster than jet fuel, so requiring new technologies. For the programme, the liquid hydrogen will need to be stored at around minus 250°C in the four cryogenic fuel tanks and the liquid hydrogen converted into gas via a new technology heat exchanger.

“Is hydrogen harder? Yes. Is it doable? Absolutely,” said a confident Ali.

During the flight test phase, data will be gathered on the condensation trails produced by the engine in different atmospheric conditions, said Michel Brioude, Chief Technology Officer at Safran Aircraft Engines. “Hydrogen combustion does not emit CO2 but it does produce three times the amount of water, so condensation trails can contribute to the greenhouse effect and we will need to measure that,” he said. “Today, we don’t know how long they exist in the atmosphere.”

Klauke told the press event that the demonstration timeline announced was fitting exactly with the 2035 entry-into-service plan outlined at the Airbus Sustainability Summit in September 2020. The plan to conduct flight tests by the end of 2026 will enable Airbus to make technology choices for the aircraft’s propulsion system in 2027, she said.

Airbus Americas Chairman Jeff Knittel described the signing of the strategic partnership between Airbus and CFM as an historic day for aviation, adding: “Hydrogen propulsion is a fundamental part of the long-term solution and we are committed to this new aviation future.”

The Airbus A380 ZEROe demonstrator showing the four liquid hydrogen tanks and the GE Passport turbofan engine mounted on the rear fuselage (top and bottom images: Airbus)

Airbus, CFM, GE and Safran executives unveil their hydrogen propulsion partnership (starts 7:45)

Mark Pilling

GreenAir Contributing Editor

• Linkedin
• Twitter

Additional reporting by Christopher Surgenor

Long-standing engine partners GE Aviation and Safran have launched a new technology demonstration programme called RISE – Revolutionary Innovation for Sustainable Engines – which is aimed at developing open rotor powerplants that can be powered by 100% sustainable aviation fuel or liquid hydrogen for the next generation of single-aisle aircraft from 2035. The two companies have also signed an agreement to extend the CFM International 50/50 partnership, which manufactures the CFM range of LEAP and CFM56 engines, to the year 2050. The RISE programme has a target of developing technologies that will deliver more than 20% greater fuel efficiency and lower CO2 emissions compared with today’s engine generation, reports Mark Pilling. Open rotor engine technology is not new but the potential fuel savings on offer have been offset in the past by an increased noise penalty. However, the partners insist noise levels will be no higher than those from current LEAP engine technology.

“It is a programme to support the future launch of a new CFM engine to succeed LEAP,” said Olivier Andriès, Chief Executive of Safran. “We must act with a burning sense of urgency, and we must rise to the challenge of decarbonisation,” said John Slattery, Chief Executive of GE Aviation, speaking alongside Andriès in Paris on 14 October during the online launch of RISE.

GE and other engine manufacturers, including Safran and Rolls-Royce, have been developing this technology for decades. GE and NASA first began working on open rotor concepts in 1970s in response to an international oil crisis and testing continued in earnest during the 1980s. When the price of oil plummeted in the mid-1990s, the viability of open rotor propulsion came into question, despite the promise of improved fuel efficiency.

However, CFM believes open fan, or open rotor, engine architecture is the game changing technology that will provide the step change to unlock the ambitious emission reduction and efficiency targets the industry is targeting, said Delphine Dijoud, Executive Manager, CFM RISE Programme, at Safran Aircraft Engines.

The partners envisage an engine mounted over or under the wing or on either side of the aft fuselage of an aircraft, and the blades not contained within a nacelle, offers significant efficiency gains compared to today’s nacelle-based high bypass ratio fans.

“We have engaged with both Airbus and Boeing on our technology plan,” said GE’s Slattery. The OEMs recognise that open rotor aircraft configurations do offer the reduction levels in emissions and boost in fuel efficiency that will be required, said Andriès, who added: “We have a deep experience of the open fan.”

For travellers, increasingly their “true north” is an awareness of the need to reduce carbon emissions, and a technology that achieves this will be a positive development, suggested Slattery.

On cabin and exterior noise, he said there would be no degradation relative to that experienced from CFM’s latest technology LEAP engine. “That’s our minimum commitment,” he promised.

According to GE Aviation’s Arjan Hegeman, General Manager for advanced technology operation, RISE will focus on three main technology pillars: advanced architecture (open rotor), advanced materials and hybrid electrification of the engine to reach the 20% target. RISE is being led by a joint GE/Safran engineering team that has laid out a technology roadmap including composite fan blades, heat resistant metal alloys, ceramic matrix composites, hybrid electric capability and additive manufacturing. RISE will use hybrid electric capability to optimise engine efficiency while enabling electrification of many aircraft systems.

The partners began collaborating on RISE in 2019 and by the end of this year there will be 1,000 engineers across the two companies working on it, reported Mohamed Ali, VP and General Manager Engineering at GE Aviation. A demonstrator engine is scheduled to begin testing at GE and Safran facilities around the middle of this decade and flight testing soon thereafter, he said.

The use of sustainable aviation fuel will be essential for RISE and it will be designed to run on 100% SAF and be compatible with liquid hydrogen, said Slattery. “Ninety percent of the engine will be the same whatever the fuel [SAF or hydrogen],” explained Andriès. He noted the recent announcement that Airbus, Safran, Dassault Aviation, ONERA and the French Ministry of Transport will launch an in-flight study at the end of 2021 to analyse the compatibility of unblended SAF with single-aisle aircraft and commercial aircraft engine and fuel systems, as well as with helicopter engines. Known as VOLCAN (VOL avec Carburants Alternatifs Nouveaux), this project is the first time that in-flight emissions will be measured using 100% SAF in a single-aisle aircraft.

Both Slattery and Andriès stressed RISE is a technology development programme and not an engine launch. That will come when an OEM launches a new aircraft, they said. Asked about competition from the other engine OEMs, Slattery believes the collective mission of the industry is ultimately to deliver sustainable aviation. “We encourage them to engage now, compete with us, bring their best engines. We welcome their competition – let’s go for it,” he said.

“Our industry is in the midst of the most challenging times we have ever faced,” said Andriès. “We have to act now to accelerate our efforts to reduce our impact on the environment. Since the early 1970s, breakthrough engine efficiency and reliability have been the hallmark of our historic partnership and our LEAP engine already reduces emissions by 15% compared to previous generation engines. Through the extension of our CFM partnership to 2050, we are today reaffirming our commitment to work together as technology leaders to help our industry meet the urgent climate challenges.”

Added Slattery: “Together, through the RISE technology demonstration programme, we are reinventing the future of flight, bringing an advanced suite of revolutionary technologies to market that will take the next generation of single-aisle aircraft to a new level of fuel efficiency and reduced emissions. We fully embrace the sustainability imperative. As we have always done in the past, we will deliver for the future.”

The original framework agreement creating CFM International as a 50/50 joint venture between the two aircraft engine manufacturers was signed in 1974. The partnership was renewed in 2008 for the launch of the LEAP engine programme. More than 35,000 CFM engines have been delivered to more than 600 operators around the globe, accumulating more than one billion flight hours.

Top image: CFM RISE – rendering of concept airframe configuration

Launch of RISE programme:

Mark Pilling

GreenAir Contributing Editor

• Linkedin
• Twitter