Assessing Environmental Benefits of Electric Aircraft Taxiing through Object-Oriented Simulation

A number of promising technologies to perform ground movements without main engines are currently being researched. Notably, onboard ground propulsion systems have been proposed featuring electric motors in the landing gear. While such on-board systems will help save fuel and avoid emissions while on ground, they add significant weight to the aircraft, which has an impact on the performances in flight. A tool to assess the global benefits in terms of fuel consumption and emissions is presented in this work. A concept of an aircraft-integrated ground propulsion system is firstly considered and its performances and weights are determined, assuming the Auxiliary Power Unit or a zero-emission device like a fuel-cell as power source for the system. Afterwards, a model of the propulsion system integrated into an object-oriented, mid-sized aircraft model is generated, capable of precisely simulating a whole aircraft mission. Two different gate-to-gate flights with realistic trajectories are simulated with a conventional aircraft and one equipped with a ground propulsion system. Finally, the emissions and fuel consumptions are compared in each flight phase. The results show a potential overall fuel saving of up to 2.6%, depending on the flight mission and the duration of the taxi phases. The associated CO₂ emission may decrease by the same amount. Furthermore, NOx, CO, and HC emissions on ground using an electrical taxiing system might be reduced by 64% to 80% compared to conventional ground operations. In conclusion, the aircraft model used in this work has proved a powerful tool to assess the performances of an electrical taxiing system and to compare different real-world scenarios.