DALLAS — This week, Emirates (EK) used 100% Sustainable Aviation Fuel (SAF) to complete ground engine testing for one of its GE90 engines on a Boeing 777-300ER (SAF).

The goal of the ground testing and analysis is to show that the GE90 engine can operate on the specially blended 100% SAF without impairing its performance. This leads to necessitating no changes to the aircraft's systems or additional maintenance for the GE90 engine or Boeing 777-300ER. Over the course of the fuel's life cycle, SAF can cut carbon emissions by up to 80%.

The airline's first experimental test flight employing 100% SAF in one engine is scheduled to take off this week.

The testing operations entailed operating one engine on 100% SAF and the other on regular jet fuel in order to further analyze the behavior and performance of the fuel system under each fuel type, compare the individual outputs of each engine and confirm that the aircraft's engine and airframe fuel systems would function without a hitch during the scheduled test flight.

At Emirates Engineering Center

The airplane underwent its usual pre-inspection procedures before the ground testing at the cutting-edge Emirates Engineering Centre in Dubai. Then, the Honeywell 331-500 auxiliary power unit (APU) was first run at 100% SAF to start the stationary operation tests.

The engines were then started by putting the APU under full load using SAF. Using the identical settings that will be utilized during the trial flight, the left engine was worked through its entire power range.

This included running at maximum speed and intensity during complete flight profile durations for the 'idle', 'take-off', and 'climb' settings. The following 15 minutes were spent with the engines set to 'cruise'. After the simulation was completed, the engines were cooled to preserve the separation of fuels; they were segregated into separate fuel tanks.

A Memorandum of Understanding (MoU) was signed by the airline, GE Aerospace, and Boeing at the Dubai Airshow 2021. This aimed to create a program for carrying out a test flight employing 100% SAF on an Emirates 777-300ER powered by GE90 engines.

Throughout 2022, Emirates has been working on SAF fuel blend testing with its partners GE Aerospace, Boeing, Honeywell, Neste, and Virent Inc., a division of Marathon Petroleum Corp.

The partners worked together on the technical analyses and operational needs surrounding ground testing and experimental flight activities to create a blend that has the same attributes and performance characteristics as conventional jet fuel.

Project Outcomes

The outcomes of this project will add to the body of knowledge and research on biofuels and the components of synthetic fuel blends. This shall help in promoting standardization and the potential approval of a 100% drop-in SAF.

The carrier will continue to develop these projects with the engine airframe manufacturers and SAF providers after the successful trial on one engine, with the ultimate goal of certifying these mixes for commercial usage. Currently, SAF is permitted to be mixed up to 50% with regular jet fuel.

Emirates actively participates in initiatives to boost SAF deployment and has long supported business and governmental efforts to promote the growth of the SAF industry. Its inaugural flight, a Boeing 777 out of Chicago O'Hare Airport (ORD), was powered by SAF combined with jet fuel in 2017. With the help of Swedavia's Biofuel Incentive Program, EK lifted 32 tons of SAF for its flights from Stockholm earlier.

Emirates received its first A380 fuelled by SAF in December 2020. Additionally, SAF now offers flights departing from Oslo.

Featured image: Emirates