Ground evaluation compared performance of different fuels, paving way for experimental test flight
Emirates has completed the ground engine testing for one of its GE90 engines on a Boeing 777-300ER using 100 per cent sustainable aviation fuel (SAF), the airline announced. One of the GE90 engines ran on 100 per cent SAF while the other ran on regular fuel as the airline analysed if the engine can run on the specially blended 100 per cent SAF without affecting its performance, requiring no modifications to the aircraft systems, or special maintenance procedures on the aircraft or GE90 engine to operate. SAF reduces carbon emissions over the fuel’s life cycle by up to 80 per cent.
The ground test results will now pave the way for the airline’s first experimental test flight using 100 per cent SAF in one engine, which is due for take-off this week.
During the ground testing, 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 per cent 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.
Last year, Emirates, GE Aerospace and Boeing signed a Memorandum of Understanding (MoU) to develop a programme for conducting a test flight using 100 per cent SAF on an Emirates 777-300ER powered by GE90 engines.
Emirates has been working with GE Aerospace, Boeing, Honeywell, Neste and Virent 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 per cent 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 per cent with conventional jet fuel.
Its first flight powered by SAF blended with jet fuel was in 2017, operating from Chicago O’Hare airport on a Boeing 777. Emirates received its first A380 powered by SAF in December 2020, and uplifted 32 tonnes of SAF for its flights from Stockholm earlier that year.
