High altitude testing of a 100% SAF-powered Gulfstream business jet shows significant non-CO2 benefits

Preliminary results from high altitude testing of a Rolls-Royce Pearl 700-powered Gulfstream G800 business jet suggest a significant measurable reduction in the particulate emissions that contribute to contrail formation when operating on neat sustainable aviation fuel. The test campaign, which marked the first 100% SAF flight of the aircraft and engine type, was designed to isolate how fuel composition influences non-CO2 emissions. The G800 was paired with a specially modified G700 transformed into a flying emissions measurement laboratory. The Gulfstream campaign was conducted in collaboration with the FAA’s Center of Excellence (ASCENT), NASA, the German Aerospace Center (DLR), Missouri University of Science and Technology, Aerodyne Research, Rolls-Royce, SAF supplier Montana Renewables and World Fuel Services.

“This campaign reflects our strategy to lead with advanced technology, real-world testing and meaningful collaboration to better understand and reduce aviation’s environmental impact,” said Mark Burns, President of Gulfstream.

The G800 and G700 operated in close formation (see photo below) that enabled researchers to capture precise, real-world measurements of particulate matter and contrail-forming atmospheric characteristics at higher altitudes – typically up to 50,000 feet for business aviation – than flown by most commercial airliners.

The campaign involved months of preparation by Gulfstream’s engineering and flight test teams, including the modification to the G700 cabin. The company’s pilots trained in simulators to execute complex formation profiles needed to capture both near-field emissions and contrail evolution several miles in-trail.

The research team compared conventional Jet A, low-sulphur Jet A and neat HEFA SAF, which contains no sulphur or aromatics.

Gulfstream says the programme has provided valuable data that will be shared with the broader aviation and atmospheric science communities. “These insights will help refine analytical models, inform future fuel standards and support the development of operational strategies to reduce aviation’s environmental impact,” it adds.

Rich Moore, a research scientist at NASA, responded: “This real-world data is essential to improving our models and understanding aviation’s broader environmental impact.”

The partnership with Gulfstream would help inform and quantify efforts to mitigate the impacts of persistent contrails, said Julie Marks, Executive Director of the FAA’s Office of Environment and Energy. “We appreciate the collaboration with industry as the FAA continues to evaluate how SAF may help reduce persistent contrails,” she added.

Observed Alan Newby, Director of Research and Technology at Rolls-Royce: “The valuable insights we have gained from these latest tests at high altitudes, as well as the data from projects like QRITOS or ECLIF3, are driving real progress in understanding aviation’s non-CO2 climate impacts and potential mitigation options.”

To date, Gulfstream says its aircraft have flown more than 3.5 million nautical miles on SAF blends. This includes the industry’s first transatlantic flight using SAF in one engine in 2011 and the industry’s first transatlantic flight powered by 100% SAF in 2023.

“As aviation continues its work in optimising environmental efficiencies, Gulfstream is focused on advancing solutions that deliver measurable impact today while shaping a more sustainable future for flight,” said Burns.

Photos: Gulfstream Aerospace

Christopher Surgenor
Editor