Aircraft retiming and rerouting in vicinity of airports

This study addresses the real-time problem of aircraft conflict detection and resolution in a terminal manoeuvring area (TMA). The problem is to take conflict-free airborne decisions on take-off and landing operations at a congested airport. Aircraft control actions at air segments and runways include timing, sequencing, holding and routing. Rescheduling and rerouting decisions aim at balancing the runway workload while minimising delay propagation. This problem can be viewed as a job shop scheduling problem with additional real-world constraints. Two formulations are analysed in which air segments, runways and holdings are modelled explicitly. In the first formulation the entrance time of each aircraft in the TMA is fixed, in the second it can be defined by the procedure. A truncated branch and bound algorithm computes aircraft schedules with fixed routes. The branch and bound is then incorporated in a tabu search scheme for aircraft rerouting. The solution approach is tested on the Rome Fiumicino airport, the main Italian airport, under congested traffic conditions and for several aircraft delay configurations. Computational results show a significant delay reduction when real-time rerouting is allowed in combination with rescheduling with respect to real-time rescheduling with fixed routes. The improvement is larger for the second formulation.