The A400M programme team with the Military Air Systems unit of the Defence and Space division has kicked off its test flight campaign with Sustainable Aviation Fuel (SAF) this summer. A first test flight using a load of 29% SAF in one of its engines proved successful; also in military aviation Airbus moves forward on its commitment to get cleaner skies.

A mixture of nerves and excitement was felt among the team members on the tarmac of Airbus´ San Pablo plant, in Seville, on an extremely hot day in July. Indeed, there was plenty to be excited about, as it was a day of `firsts´: the first test flight with SAF was finally happening with an Airbus A400M.

The MSN4 or ´Grizzly 4´, as it is known among the team, entered the runway with one of its engines, specifically engine number 2, with a blended load of 29% SAF. “For this first flight, we are using a type of SAF called HEFA (Hydroprocessed Esters and Fatty Acids) which is made of residuals of oils, vegetables and fats, and also free of aromatics and Sulphur, so it is very efficient and good for the engines”, explained Ana Belén Blanco, Technical Leader for SAF in A400M. “It is a drop-in fuel, so there is no need to modify the engines´ systems and there are no technical limitations”, she said. For this first test flight, the use of SAF was limited to one engine to better analyze the fuel system´s behavior feeding a single engine.

The flight, which took off from the San Pablo plant runway in Seville, headed towards the North of Huelva and then landed back safely in Seville, making a trip of more than an hour in total. The satisfaction of the crew was already evident on their faces while they disembarked the aircraft, ready to share the outcome. “During the flight, we performed a close comparison between engine number 2, the one using SAF, and the other 3 engines using standard fuel Jet A1, so we had a very good opportunity to compare the performance of the different fuels”, said César González, Flight Test Engineer at Airbus Defence and Space. “The results we got confirmed that using this blended SAF does not affect engines or aircraft performance, so the A400M can receive the whole potential of it in terms of environmental benefit”, González added.

SAF is a proven alternative fuel that can reduce life cycle CO2 emissions by up to 85% compared to conventional fuel. This first flight of an A400M using SAF demonstrated that both the aircraft and its TP400-D6 engines, not tested before with SAF, are aligned with these new fuel requirements with a blend of 50% certified SAF for a more sustainable military aviation.

Airbus and EuroProp International, which is responsible for TP400-D6 turboprop’s engine design, development, manufacturing and support, have agreed to establish the roadmap towards 100% SAF certification together, making this first flight a step forward towards this goal.

“This flight is a significant step forward, and relying on the expertise of our parent companies, we are confident that TP400-D6 robust design will enable us to reach the highest SAF standards”, said Stephan Schlisske, Head of Design Organisation of Europrop International.

More than 100 A400M aircraft are deployed in 8 different countries, so offering them the capability to use SAF is one of Airbus’ priorities. “Our operators had expressed their willingness to use SAF in their military operations, and we are here to respond to their needs”, said Rocío Gutierrez Alonso, Chief Engineer of A400M Power Plant. After running all flight test procedures and performing the required ground tests analysis, the engineering team gave the green light to this first test flight with SAF.

`Grizzly 4´: An experienced warrior for a crucial mission

For such an important mission, one of the most experienced Airbus “warriors” was needed. The “Grizzly 4”, on duty since 20th December 2010, was the one selected among the “troops” to perform this first test flight with SAF among Military Air Systems at Airbus. And so the MSN4 finds itself guiding its successors into the future: the decarbonization of military aviation.

MSN4 has been used for all kinds of tests through the years. Among others, it was determinant for the development and certification of AAR capabilities as a tanker and receiver and also for cargo and parachute drops, as it was designed in such a way that the cargo hold was free of instrumentation and therefore, fully usable for aerial delivery or additional fuel tanks (CHT). This first flight with SAF is number F994 in the MSN4´s impeccable service record, so it is only six more flights away from a well-deserved “retirement” after nearly 2,000 flight hours.

The `Grizzly 4´ shows its wear and tear from all the operations, but its robustness, capabilities and reliability have remained intact throughout its career. So, still in good shape to perform one of its last and crucial missions: leading the path to a more sustainable military aviation at Airbus. The past and the future of one of Airbus’ core military aircraft, united by a common goal.

The fascinating race towards sustainable military aviation

This first flight, conducted with one engine using blended SAF, is a first step on the long-term roadmap in which Airbus is embarked on towards achieving 100% certified SAF readiness and certification for the A400M.

Airbus A400M operators recently showed their interest in using blended 50% certified SAF, so Airbus’ objective was to perform this first test flight as part of its best practices. Following its successful performance, A400M operators can now fly using a load of up to 50% certified blended SAF, and Airbus will continue supporting them along the way.

“Having cleaner skies and contributing to a more resilient planet is a goal shared with our operators worldwide, and so it is our responsibility to respond to the challenges this implies. Any of their missions is also ours, so performing safer and cleaner military operations is the immediate one”, said Jean-Brice Dumont, Head of Military Air Systems at Airbus Defence and Space.

Furthermore, Airbus, OCCAR and the A400M Nations are engaged in initial discussions to develop the roadmap towards the certification and operational use of 100% SAF in aircraft.

On this SAF project, all Airbus divisions are working closely to share knowledge and lessons learned. “This first flight of an A400M using SAF is a first step in our division that creates the momentum to progress steadily and persistently at an efficient pace along this path towards sustainability”, Gutiérrez stated. In order to move forward, more flight tests with SAF are planned for the coming months for the C295 and the A330 MRTT, which will soon join the A400M in this fascinating race towards sustainable military aviation.

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