Rolls-Royce and Gulfstream Aerospace have conducted a test flight of an ultra-long range business jet powered 100 per cent by SAF. The test took place on the BR725-powered Gulfstream G650 over Gulfstream's headquarters in Savannah, Georgia.

Demonstrating that current Rolls-Royce engines for business jet and large civil applications can operate with 100 per cent SAF as a full drop-in option, this test lays the groundwork for moving SAF towards certification. At present, SAF is only certified for blends of up to 50 per cent with conventional jet fuel and can be used on all current Rolls-Royce engines.

The SAF that was used in the test consists of two components: HEFA (hydroprocessed esters and fatty acids) produced from waste fat and waste plant oils by low-carbon fuel specialist World Energy in Paramount, California; and synthesised aromatic kerosene (SAK) made from waste plant-based sugars by Wisconsin-based Virent. This innovative and fully sustainable fuel in development eliminates the need for the addition of further petroleum-based components and enables a 100 per cent drop-in SAF that can be used in existing jet engines and infrastructure without any modifications. This sustainable fuel has the potential to reduce net CO2 lifecycle emissions by about 80 per cent compared to conventional jet fuel, with the possibility of further reductions in future.

R-R Deutschland chief engineer, business aviation and engineering director Dr Joerg Au says: “Sustainable aviation fuels are essential for the decarbonisation of the skies as they have the potential to significantly reduce the carbon emissions of aviation, and we have already proved they can be used as a drop-in fuel to power existing engines. This flight test with Gulfstream is another proof point that demonstrates the compatibility of our engines with SAF, bringing us another important step closer to enabling our customers to achieve net zero carbon emissions.”

“At Gulfstream, leading our industry closer to decarbonisation is a long-standing priority, and testing, evaluating and promoting new developments in SAF takes us another step closer to that goal,” adds president Mark Burns. “We are grateful for our partnership with Rolls‑Royce to be able to demonstrate yet another milestone in these efforts."

The BR725-powered G650 aircraft family holds more than 120 world speed records, including the speed record for the farthest flight in business aviation history. Since its entry into service in 2012, the G650 aircraft family has established a reputation for excellent reliability, efficiency and speed, combined with outstanding environmental performance.

Gulfstream's sustainability strategy encompasses three pillars, namely energy and emissions; operations; and culture and learning. It supports industry goals established by the NBAA, GAMA and IBAC. The goals are a two per cent improvement in fuel efficiency per year from 2010 to 2020; carbon-neutral growth from 2020 onward; and net-zero carbon dioxide emissions by 2050.

“Gulfstream has long prioritised sustainable products and practices through innovations in aerodynamics, aircraft technologies, engineering, manufacturing and infrastructure, as well as in facilities operations and our investments in SAF research and development,” says Burns.