TOULOUSEA team of aerospace specialists has launched the world’s first in-flight emissions study using 100% sustainable aviation fuel (SAF) on a wide-body commercial passenger aircraft.



Airbus, German research center DLR, Rolls-Royce, and SAF producer Neste have teamed up to start the pioneering ‘Emission and Climate Impact of Alternative Fuels’ project looking into the effects of 100% SAF on aircraft emissions and performance.

Findings from the study - to be carried out on the ground and in the air using an Airbus A350-900 aircraft powered by Rolls-Royce Trent XWB engines - will support efforts currently underway at Airbus and Rolls-Royce to ensure the aviation sector is ready for the large-scale use of SAF as part of the wider initiative to decarbonize the industry.

Fuel-clearance engine tests, including a first flight to check operational compatibility with the aircraft’s systems, started at Airbus’ facilities in Toulouse, France, this week. These will be followed by the groundbreaking flight-emissions tests due in April and resuming in Q4 2021, using DLR’s Falcon 20-E ‘chase plane’ to carry out measurements to investigate the impact of sustainable-fuel emissions. Meanwhile, further ground tests measuring particulate-matter emissions are set to indicate the environmental impact of SAF-use on airport operations.

Both the flight and the ground tests will compare emissions from 100% SAF made from HEFA (hydro-processed esters and fatty acids) against those produced by fossil kerosene and low-sulfur fossil kerosene.

The SAF will be provided by Finnish oil-refining company Neste, a leading worldwide supplier of sustainable fuel. Additional measurement and analysis for the characterization of the particulate-matter emissions during the ground testing will be delivered by the UK’s University of Manchester and the National Research Council of Canada.

“SAF is an important part of Airbus' ambition to decarbonize the aviation industry, ensuring a sustainable future for air travel,” said Steven Le Moing, New Energy Programme Manager, Airbus. “It is a ready-to-use solution for current fleets and remains the most viable, long-term solution for long-haul flights where other technologies, such as hybrid-electric and hydrogen, are further from maturity.

“SAF is currently only permitted at up to a 50% volume blend with fossil kerosene but this exciting collaboration between industry, academia, and the government will provide us with a unique insight into how gas-turbine engines function using 100% SAF. The identification of the potential for emissions reductions, and the environmental impact of using such fuels in flight, will further lay the groundwork for its future certification.”

Dr. Patrick Le Clercq, Project Manager at DLR, said: “By investigating 100% SAF, we are taking our research on fuel design and aviation climate impact to a new level. In previous research campaigns, we were already able to demonstrate the soot-reduction potential of between 30 and 50 percent blends of alternative fuels, and we hope this new campaign will show that this potential is now even greater.

“DLR has already conducted extensive research on analytics and modeling as well as performing ground and flight tests using alternative fuels with the Airbus A320 ATRA research aircraft in 2015 and in 2018 together with NASA.”

Simon Burr, Director Product Development and Technology, Rolls-Royce Civil Aerospace, added: “In our post-COVID-19 world, people will want to connect again but do so sustainably. For long-distance travel, we know this will involve the use of gas turbines for decades to come. SAF is essential to the decarbonization of that travel and we actively support the ramp-up of its availability to the aviation industry. This research is essential to support our commitment to understanding and enabling the use of 100% SAF as a low-emissions solution.”

Jonathan Wood, Vice President Renewable Aviation at Neste, said: “We’re delighted to contribute to this project to measure the extensive benefits of SAF compared with fossil jet fuel and provide the data to support the use of SAF at higher concentrations than 50%. Independently verified analysis shows 100% Neste MY Sustainable Aviation Fuel delivers up to 80% reduction in greenhouse gas emissions compared to fossil jet fuel use when all life-cycle emissions are taken into account; this study will clarify the additional benefits from the use of SAF."