In-flight emission tests using 100 percent SAF and a HEFA/Jet A-1 fuel blend resumed this month, while ground-based emissions testing to quantify the benefits of SAF on local air quality were also performed. The research team found SAF releases fewer particulates than conventional kerosene at all tested engine operating conditions, which points to the potential for reduced climate impact and improvement in air quality around airports. In addition, SAF has lower density but higher energy content per kilogram of fuel compared to conventional kerosene, which brings some aircraft fuel-efficiency advantages due to lower fuel burn and less fuel mass on board to achieve the same mission. Detailed analysis by the team is on-going. "Engines and fuel systems can be tested on the ground but the only way to gather the full set of emissions data necessary for this programme to be successful is to fly an aircraft in real conditions," said Steven Le Moing, New Energy Programme Manager at Airbus.