UK-based global major propulsion and power systems group Roll-Royce announced on Wednesday that it had successfully tested its latest generation of business jet engines using 100% sustainable aviation fuels (SAF). The power plants concerned are the Pearl 15 and the Pearl 10X. The former powers the Bombardier Global 5500 and Global 6500 aircraft, while the latter will power the Dassault Falcon 10X (the French airframer’s ultra-long-range flagship business jet).

Rolls-Royce’s business jet engines are designed and built in Germany, and the tests took place in Dahlewitz, in that country, at the headquarters of Rolls-Royce Business Aviation. In addition to the 100% SAF tests on both engines, the company ran comparative tests on the Pearl 10X engine, running the same engine on 100% Jet A-1 fuel and on 100% SAF.

“[SAF] are a key element of our sustainability strategy, as they will play an important role in decarbonising long-haul flight,” highlighted Rolls-Royce director: business aviation Dr Dirk Geisinger. “With its outstanding environmental performance, the Pearl family is already setting new standards in the ultra-long-range corporate jet market.”

The SAF used in the tests was made from hydro-processed esters and fatty acids, a feedstock usually referred to by the acronym HEFA. This is derived from waste materials such as used cooking oils and waste fat. HEFA-based SAF could potentially reduce aeroengine net lifecycle carbon dioxide emissions by some 80%, compared with conventional jet fuel.

Regarding the comparative fuel tests run on the Pearl 10X, these were run under standard certification conditions. The tests confirmed that the SAF produced cleaner combustion than the conventional fuel. The SAF produced “significantly lower” amounts of non-volatile particulate matter. Combined with the Pearl 10X’s low nitrogen oxides combustor technology and its additive manufactured (3D printed) combustor tiles, the result was a reduction in all emissions.

Currently, worldwide, regulators only permit commercial and business aircraft to fly with fuel blends of up to 50% SAF. These Rolls-Royce tests are helping pave the way to the certification of 100% SAF. By the end of this year the group will have demonstrated that all its current production Trent and business jet engines are compatible with 100% SAF.