In a project with NASA and United Airlines, Boeing is to carry out in-flight sustainable aviation fuel (SAF) testing.
The test will measure how SAF affects contrails and non-carbon emissions, in addition to reducing the fuel’s lifecycle climate impact.
Boeing’s second ecoDemonstrator Explorer, a 737-10 destined for United Airlines, will fly with 100 per cent SAF and conventional jet fuel in separate tanks and alternate fuels during testing.
Flying behind the commercial jet will be NASA’s DC-8 Airborne Science Lab which will measure emissions produced by each type of fuel and contrail ice particles.
NASA satellites will also capture images of contrail formation as part of the testing.
It is hoped that the research will help to understand how advanced fuels, engine combustor designs and other technologies may reduce atmospheric warming.
For example, according to a press release from Boeing, tests will assess how SAF affects the characteristics of contrails, the persistent condensation trails produced when airplanes fly through cold, humid air. While their full impact is not yet understood, some research has suggested certain contrails can trap heat in the atmosphere.
The project is the latest phase in a multi-year partnership between Boeing and NASA to analyse how SAF can reduce emissions and enable other environmental benefits.
Compared to conventional jet fuel, SAF – made from a range of sustainably produced feedstocks – can reduce emissions by up to 85 per cent over the fuel’s lifecycle and offers the greatest potential to reduce aviation CO2 over the next 30 years.
SAF also produces less soot which can improve air quality near airports.
Chris Raymond, Boeing’s chief sustainability officer, said: “We are honoured to collaborate with NASA, United Airlines, and other valued partners on research that will strengthen the industry’s understanding of the benefits of SAF beyond reducing carbon emissions.
“We’ve solved hard problems before, and if we continue to take meaningful actions, I’m confident we’ll achieve a more sustainable aerospace future, together.”
Rich Wahls, NASA mission integration manager for the Sustainable Flight National Partnership, said: “Flight testing is complex and resource-intensive, yet it’s the gold standard for understanding how sustainable aerospace innovations affect changes in contrails and climate.
“This is why we’re bringing NASA’s DC-8 to bear on this collaboration, where the valuable flight data will improve our predictive models.”
Lauren Riley. United Airline’s chief sustainability officer, said: “This collaboration between Boeing, NASA and United has the potential to not only help us better understand contrails but to provide the full scope of what our transition to SAF can provide beyond greenhouse gas (GHG) reductions.”
World Energy will supply the SAF for the tests from its Paramount, California, facility. Other support for the test includes: the US Federal Aviation Administration (FAA) is providing funding through the ASCENT Center of Excellence; GE Aerospace is providing technical expertise and project funding; and the German Aerospace Center (DLR) is providing experts and instrumentation.
GE Aerospace vice president of engineering, Mohamed Ali, said: “We at GE Aerospace proudly support this ground-breaking research collaboration that will deepen our scientific understanding of the impact of SAF on emissions for a more sustainable future of flight.”
Markus Fischer, DLR divisional board member for aeronautics, said: “To achieve climate-compatible aviation, we need close international cooperation. The German Aerospace Center has decades of experience in research on the climate impact of the entire aviation system by advancing measurement technology and simulations.
“The continuation of transatlantic cooperation now finds a new summit and underlines the international commitment to reduce the climate impact from aviation’s CO2 and non-CO2 effects.”
The Boeing ecoDemonstrator programme was expanded this year to include Explorer airplanes focused on short-term, specific test projects.
Boeing and NASA conducted SAF emissions ground testing on an Alaska Airlines 737-9 in 2021 and ecoDemonstrator 777-200ER and 787-10 flight-test jets in 2022.
Boeing says it is committed to deliver commercial airplanes compatible with 100 per cent SAF by 2030.
The 737-10 is the largest airplane in Boeing’s single-aisle 737 MAX family, which reduces fuel use and emissions by 20 per cent compared to airplanes it replaces.
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