Towards a Mechanism for Ensuring Equity Over Time Among Airspace Users in Collaborative Flight Prioritization

In air traffic flow management (ATFM), the EUROCONTROL Network Manager regulates flights in the case of unexpected events that temporarily reduce airport capacity. In this case, regulated flights receive a new target time of arrival (TTA) following a first-planned, first-served approach. These regulations typically result in flight delays and additional delay costs for airspace users (AUs) and the arrival airport. The HARMONIC project, which is funded by the SESAR Joint Undertaking within the EU Horizon Europe program, develops, among others, a Target Time Management System (TTMS) to enable collaborative flight prioritization and optimization based on preferences of the AUs and the airport. The TTMS was successfully tested in live trials at Zurich Airport, with results indicating increased arrival punctuality and fewer missed connections. Although short-term inequity is acceptable to improve overall efficiency in a given situation, the TTMS shall ensure long-term equity, i.e., no AU is favored or disfavored compared to the others over time. In this regard, one challenge is to design an Equity Mechanism as part of the TTMS to ensure long-term equity across AUs. In this paper, we introduce an Equity Mechanism that modifies the preferences of AUs. We investigate various configurations of three different strategies for adjusting the preferences of AUs with the Equity Mechanism. We use the Theil index to measure inequity and preferences from 51 regulations obtained during the live trials at Zurich Airport for re-running each optimization in a controlled lab environment. Our results show that some configurations of the Equity Mechanism can reduce the Theil index over time, i.e., successfully improve long-term equity, while having only a minor impact on the quality of the flight lists found by the TTMS.

Keywords: air traffic control, flight prioritization, equity