Results from the world’s first in-flight study of using 100 percent sustainable aviation fuel in both engines of a commercial aircraft indicate significant reductions in soot particles and contrail ice crystals compared to conventional Jet A-1 fuel. The ECLIF3 study, conducted by Airbus, Rolls-Royce, the German Aerospace Centre, and SAF producer Neste, measured the emissions impact on an Airbus A350 powered by Rolls-Royce Trent XWB engines.

The study found that using unblended SAF reduced the number of ice crystals per mass consumed by 56 percent, potentially mitigating the climate-warming effect of contrails. Global climate model simulations by DLR estimated a reduction in radiative forcing by at least 26 percent with 100 percent SAF compared to Jet A-1 fuel, demonstrating that SAF can significantly reduce aviation’s climate impact by addressing non-CO2 effects in addition to lowering CO2 emissions over the fuel’s lifecycle.

Alexander Kueper, vice president of renewable aviation business at Neste, highlighted that the study confirms the lower climate impact of 100 percent SAF due to the absence of aromatics. Markus Fischer, DLR divisional board member for aeronautics, noted the significant reduction in contrail formation, underscoring SAF’s role in climate-compatible aviation. Mark Bentall, head of research & technology programme at Airbus, and Alan Newby, director of research & technology at Rolls-Royce, both emphasised the additional benefits of SAF in reducing non-CO2 emissions.

The findings, published in the Copernicus journal Atmospheric Chemistry & Physics, provide the first in-situ evidence of the climate impact mitigation potential of pure SAF on a commercial aircraft. The ECLIF3 programme, which included researchers from the National Research Council of Canada and the University of Manchester, conducted both in-flight emissions tests and ground tests in 2021.

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