Emirates used 100% sustainable aviation fuel to successfully complete the 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, 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 ground test results will now pave the way for the airline’s first experimental test flight using 100% SAF in one engine, which is due for take-off this week. The testing activities involved running one engine on 100% SAF and the other on conventional jet fuel to better analyse the fuel system´s behaviour and performance under each fuel type, compare specific outputs of each engine, and ensure seamless operation of the aircraft’s engine and airframe fuel systems during the planned test flight.

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During the ground testing at the state-of-the-art Emirates Engineering Centre in Dubai, the aircraft first went through its standard pre-inspection activities. After that, the stationary operating testing began by first running the Honeywell 331-500 auxiliary power unit (APU) on 100% SAF. The APU was then put under full load with SAF to start the engines. The left engine was exercised through its full power range, utilising the same settings that will be used for the experimental flight.

This included idle, ‘take-off’ and ‘climb settings’ at full flight profile durations, running at maximum speed and intensity. Engines were then run at ‘cruise’ settings for 15 minutes. After the simulation ended, the engines were cooled down. Fuels were isolated in separate fuel tanks to maintain segregation of test fuels. Upon completion of the ground test, engine data was downloaded for review, comparison, and analysis.

Emirates has been working with its partners GE Aerospace, Boeing, Honeywell, Neste and Virent  Inc., a subsidiary of Marathon Petroleum Corp throughout 2022 on SAF fuel blend testing. The partners have developed a blend with the same qualities and performance characteristics of conventional jet fuel and have collaborated on the technical analysis and operational requirements surrounding ground testing and experimental flight activities.

The results of this initiative will provide additional data and research around synthetic fuel blend components and biofuels, supporting standardization and future approval of 100% drop-in SAF. Following the successful trial on one engine, Emirates will then continue to develop these initiatives with the engine airframe manufacturers as well as SAF providers with the goal of certifying these blends for commercial use. Currently, SAF is approved for use in blends of up to 50% with conventional jet fuel.