Review of advanced low-emission technologies for sustainable aviation

Turbofan engines are the most widely used propulsion technology in commercial transport aircraft and are directly involved in many of the environmental impacts of aviation. Advancements in turbofan technology have thus a very significant potential in reducing aviation impacts on the environment. This article reviews the main technological advances currently being pursued in low-emission aircraft propulsion including: combustion and thermofluidic enhancements, gearbox technology, lightweight materials and intelligent engine health management systems. The paper discusses some key opportunities and challenges for these new technologies, with a particular outlook on the historical emission trends. Particularly, historical records from the ICAO aircraft engine emissions databank are used to extrapolate current trends and the progress against the ambitious targets set by international bodies. The analysis highlights that the sustained investments made by the aviation industry have yielded progressively diminishing returns and that the emission objectives will not be achieved at the current pace. Disruptive technological advances will therefore be required to significantly improve the fuel efficiency and mitigate environmental impact of commercial transport aircraft in the future.