Featured image: Airbus

First In-flight SAF Study Shows Major Emission Reductions

DALLAS — In a groundbreaking in-flight study, an Airbus A350 using 100% sustainable aviation fuel (SAF) demonstrated significant reductions in soot particle emissions and contrail ice crystal formation compared to conventional aviation fuel.

The ECLIF3 study, a collaboration between Airbus, Rolls-Royce, the German Aerospace Center (DLR), and SAF producer Neste, measured emissions from both engines of the A350, powered by Rolls-Royce Trent XWB engines. The results showed a 56% reduction in contrail ice crystals, suggesting a notable decrease in climate-warming effects.

According to the Airbus release, global model simulations by DLR estimate a 26% reduction in contrails' climate impact with 100% SAF. This study, published in the journal Atmospheric Chemistry & Physics, provides the first in-flight evidence of the potential climate benefits of using 100% SAF in commercial aviation.

Today, Cathay Pacific partnered up with Singapore Airlines to Promote SAF. Photo: Christian Winter/Airways

Comments from Study Stakeholders

"The results from the ECLIF3 flight experiments show how the use of 100 percent SAF can help us to significantly reduce the climate-warming effect of contrails, in addition to lowering the carbon footprint of flying – a clear sign of the effectiveness of SAF towards climate-compatible aviation," said Markus Fischer, DLR Divisional Board Member for Aeronautics.

Mark Bentall, head of Research & Technology Programme, Airbus, said, "We already knew that sustainable aviation fuels could reduce the carbon footprint of aviation. Thanks to ECLIF studies, we now know that SAF can also reduce soot emissions and ice particulate formation that we see as contrails. This is a very encouraging result, based on science, which shows just how crucial sustainable aviation fuels are for decarbonising air transport."

"SAF is widely recognized as a crucial solution to mitigating the climate impact of the aviation sector, both in the short term as well as the longer term. The results from the ECLIF3 study confirm a significantly lower climate impact when using 100% SAF due to the lack of aromatics in Neste’s SAF used, and provide additional scientific data to support the use of SAF at higher concentrations than currently approved 50%," said Alexander Kueper, Vice President Renewable Aviation Business at Neste.

Alan Newby, Rolls-Royce, Director Research & Technology, said, "Using SAF at high blend ratios will form a key part of aviation's journey to net zero CO2. Not only did these tests show that our Trent XWB-84 engine can run on 100% SAF, but the results also show how additional value can be unlocked from SAF through reducing non-CO2 climate effects as well."

Pre-order the 2025 Airways Calendar