Airbus, German research center DLR, Rolls-Royce, and sustainable aviation fuel (SAF) producer Neste have launched what they lay claim as the first in-flight emissions study using 100 percent SAF on a widebody commercial passenger aircraft, the companies said Thursday.

Findings from the Emission and Climate Impact of Alternative Fuels (ECLIF) study—to involve tests on the ground and in the air using an Airbus A350-900 aircraft powered by Rolls-Royce Trent XWB engines—will support sustainability efforts already underway at Airbus and Rolls-Royce. Fuel-clearance engine tests, including a first flight to check operational compatibility of using 100 percent SAF with the aircraft’s systems, started at Airbus’s facilities in Toulouse, France, this week. Plans call for flight-emissions tests to start in April and resume in the autumn, using DLR’s Falcon 20E “chase plane” to measure the emissions impact of using SAF. Meanwhile, further ground tests measuring particulate-matter emissions will gauge the environmental effects of SAF use on airport operations. 



Both the flight and the ground tests will compare emissions from the use of 100 percent SAF produced with HEFA (hydroprocessed esters and fatty acids) technology against those from fossil kerosene and low-sulfur fossil kerosene. 



Neste will provide the SAF while the UK’s University of Manchester and the National Research Council of Canada provide further measurement and analysis of particulate-matter emissions during the ground testing.

“SAF is a vital part of Airbus's ambition to decarbonize the aviation industry and we are working closely with a number of partners to ensure a sustainable future for air travel,” said Airbus new energy program manager Steven Le Moing. “Aircraft can currently only operate using a maximum 50 percent blend of SAF and fossil kerosene; this exciting collaboration will not only provide insight into how gas-turbine engines function using 100 percent SAF with a view to certification but identify the potential emissions reductions and environmental benefits of using such fuels in flight on a commercial aircraft too."

Neste vice president for renewable aviation in Europe Jonathan Wood noted that independent analysis has already shown that Neste SAF could deliver up to an 80 percent reduction in greenhouse gasses compared with fossil fuel.

According to DLR’s ECLIF project manager, Patrick Le Clercq, previous research campaigns have demonstrated a soot-reduction potential of between 30 and 50 percent. The partners hope this study shows an even greater potential. “By investigating 100 percent SAF, we are taking our research on fuel design and aviation climate impact to a new level,” he said. “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.”