Including linear holding in air traffic flow management for flexible delay handling

This paper introduces a strategy to include linear holding into air traffic flow management (ATFM) initiatives, together with the commonly used ground holding and airborne holding measures. In this way, ATFM performance can be improved when handling delay assignment with uncertainty. Firstly, a trajectory generation method is presented, aiming at computing, per flight, the maximum linear holding realizable using the same fuel as the original nominal flight. This information is assumed to be computed and shared by the different airlines and it is then used to build a network ATFM model to optimally assign ATFM delays, in the scope of trajectory based operations. Hence, the best distribution of delay is optimized at given positions along the flight trajectory (combining the three holding practices together) and taking into account the cost of delay, especially in the fuel consumption. The problem is formulated as a mixed integer linear programming and solved with a commercially-of-the-shelf solver. An illustrative example is given, showing that under the circumstance of capacity recovered ahead of schedule, including linear holding contributes to a notable delay reduction compared to the case where only ground and/or airborne holding apply.