Airbus may have decided to halt production of its A380 double-decker jet more than three years ago, but the company is now using one of those giant planes as a testbed to experiment with technology that could play a role in the future of aviation. Last Friday, an A380 test plane flew for about three hours with one of its four engines powered by 100% sustainable aviation fuel.
Airbus flew the same A380 again today, this time for around two hours, and again with an engine running on 100% sustainable aviation fuel, or SAF. During these tests, the aircraft’s other three engines burned conventional jet fuel.
Airbus has already flown other aircraft using 100% sustainable aviation fuel – its A350 and A319neo last year – but these recent flights mark the first time it has experienced the A380, the world’s largest passenger jet. that is. Steven Le Moing, Airbus’ SAF program manager, describes the performance of the SAF-powered engine as completely “normal” and identical to what they had seen in previous tests on the other aircraft.
The plane’s test pilot, Wolfgang Absmeier, reported the same. “We didn’t notice any difference, from a pilot’s perspective,” he said in a video. “The engineers in the back, they were looking at 1,000 parameters, but at first glance there was no difference.”
Commercial planes are already allowed to fly on a mixture of regular jet fuel and SAF – up to 50% SAF – but what makes these tests interesting is that one engine was running on 100% aviation fuel. sustainable. In this case, the fuel in question came mainly from “used cooking oil, as well as other used fats”, explains Airbus. It’s called a HEFA fuel, which stands for Hydrotreated Fatty Acids and Esters.
[Related: All your burning questions about sustainable aviation fuel, answered]
Joshua Heyne, associate professor of mechanical and aerospace engineering at the University of Dayton, said “there is industry interest in switching to the fuel that Airbus tested for this flight.”
However, he says questions remain about using this type of SAF in 100% form, as opposed to blending with regular kerosene. His first concern is its compatibility with aircraft materials, as this could potentially impact seals or O-rings in the system and cause leaks.
The second is the possibility of the fuel affecting the way the aircraft measures the amount of fuel in the tanks, as it could have a different density compared to traditional jet fuel. Le Moing, of Airbus, says this second issue has been on their radar. “One of the topics we explore is the behavior of the gauging system,” he says.
The reason companies like Airbus are interested in sustainable aviation fuels is that they represent a way to make the industry greener and, ideally, contribute less to climate change. Sustainable aviation fuels are a complex subject – here’s an explainer – but they should have a lower carbon footprint than regular fuels when considering their entire life cycle. Heyne says HEFA fuels also produce less soot and are also less likely to create contrails.
Besides this Airbus test in the A380 and its other tests last year, other companies have tested the use of sustainable aviation fuel. For example, United operated a passenger flight on a 737 MAX last year, with one of its engines burning 100% sustainable aviation fuel.
Airbus even intends to use an A380 to test hydrogen fuel, although that is several years away.
Heyne says the aviation industry is interested in the HEFA-type sustainable aviation fuels that Airbus has tested, but he notes that supply availability could be a challenge. “Unfortunately, there just isn’t a lot of used cooking oil – there isn’t enough to replace all the aviation fuel we need,” says Heyne, “so we have to look at ‘other ways’.
Watch a video of the flight below: