Sustainable Aviation Fuel Effects on Aircraft Engine Particle Emissions Measured During the 2024 Gulfstream Ground Test

Business aviation is an early adopter of sustainable aviation fuel (SAF), and there is limited quantifiable information on the benefits of SAF on business aviation aircraft. Here, we present an overview of emissions measured from one of two Rolls-Royce Pearl 700 engines on a Gulfstream G700 aircraft as it operated on 100% SAF, 100% petroleum-based Jet A, and a 30/70 blend of SAF and Jet A. Particle and trace gas measurements were sampled at a downwind distance of 20 meters, which allows ample time for the exhaust plume to cool, mix with ambient air, and condense semi-volatile chemical species from the vapor to aerosol phase. While it has long been known that aircraft engines emit non-volatile soot particles that have impacts on surface air quality and contrails at cruise altitudes, the potential importance of these semi-volatile aerosols has recently come to the fore as the aviation industry seeks to understand how changing jet fuel composition and/or engine lubrication oil system breathers may mitigate semi-volatile particle formation. The 2024 Gulfstream test employed a novel diversion approach that was used to separate the effects of the combustor from the oil system breather. Here, we present an overview of the test set up and execution as well as particle emissions indices for the three different fuels.