Reducing CO2 emissions of arrivals by acting on departure times: A perspective for 30 European airports

This paper investigates the reduction of airborne delays by acting on departure times as one option to act rapidly on CO2 emissions. Following our previous work exploring the theoretical feasibility, we performed a trade-off analysis at European level driven by a cost function integrating airborne, ground and extra delay, with different weightings. We relied on a model of the today arrival flow management process with a simplified mechanism to trigger ground delays and with realistic uncertainties. We added a control of airborne delays with a ground delay capping of 30 minutes. We considered 30 European airports and selected fair weather days in 2019 for a total of more than 2 million flights. The control parameters were optimized according to a cost function for each airport and per day. The medium cost scenario leads to an average reduction per flight during peak periods of 2.5 minutes of airborne delays and 194 kg of CO2 emissions, with airborne and ground delays of 5.2 and 4.4 minutes inducing an extra delay of 0.8 minutes. For all the selected days, the cumulated reductions of airborne delays and CO2 emissions reach 13k hours and 61k tons respectively, corresponding to a reduction of 11%, with 15% of traffic concerned. No loss of runway pressure was observed. 50% of the gain may be obtained with 7 airports and 80% with 14 airports. These trends confirm the interest of developing the idea further. Future work should involve in particular the analysis of the impact on airlines operations, at departure airports and on the network.