AIRPORT SLOT SCHEDULING PROBLEM WITH EFFICIENCY, FAIRNESS AND ACCESSCIBILITY CONSIDERATIONS

29 th January, 2019.

The demand of air transport grows rapidly, which leads to serious problem due to the inadequate capacity of airport. One of the main problem is the imbalance between demand for airport services and supply of the required airport resources. In more detail, the airports capacity cannot supply enough for demand, however its infrastructure cannot be expanded in the short term to meet its requirement. This airport is called by “coordinated”. In reality, 170 of the major airports around the world are schedule coordinated airports (IATA, 2014a).
Slots here mean the capacity of schedule coordinated airports. Scheduling airport slot scheduling is the way to express how to manage effectively capacity. Schedule displacement is the metric/ factor to assess the efficiency, which is the difference between the requested time for one slot and actually allocated time for this slot. However, beside of efficiency, how the airport treat fairly with every airlines, and how many slots should be allocated for airlines connecting small remotely located airports with the hub airports are also the main concerns. But what is fairness? It means that the schedule displacement for each airlines should be proportional to the number of slots the specific airline has requested. So in order to consider simultaneously schedule efficiency, fairness and airport accessibility, the multi-objective model should be suggested. So, the objective function will only include the efficiency and fairness of schedule, because the airport accessibility can be modelled as a constraint. In the first formulation, the schedule displacement metric is used to express schedule efficiency.
Denote the set of coordination time intervals, \(M\) the set of movement and \(t_m\) is the requested time interval.
Let \(A\) be the set of airlines and be the set of movements requested by airline a.
Let

.
The bi-objective model with fairness, efficiency and accessibility is given by

Where
If , the schedule delay experienced by airline a is proportional to the number of slots requested by this airline; otherwise it implies the disproportional delay (either higher/ lower delay schedule). Due to the constraints, in general, it is impossible to achieve .
Therefore, the variance of is to express the fairness objective. There are some constraints for the optimisation problem::
  • The accessibility constraint: a minimum number of slots will be allocated to the flights connecting small remotely located regional airports with a major airport i.e. the number of intervals that an airline is willing to accept for re-scheduling flights connecting small remotely located airports and the rest of the hub airport has the lower bound.
  • The total number of movements scheduled during a given time interval is less than or equal to the available capacity.
  • The aircraft turnaround time constraint: The minimum length of arrival time and departure time is the aircraft turnaround time.
  • Every movement must be allocated to only one time interval.

In the second formulation, a weighted displacement metric is introduced to express schedule efficiency by the aircraft seat capacity and flight distance. To find more detail, please see the reference paper.
Results obtained from the proposed models will explain somehow the trade-off between the efficiency and fairness. Sensitivity analyses can represent the relationship between declared capacity and schedule delay in a medium size coordinated airport.
Reference:
1. Modelling and Solving the Airport Slot Scheduling Problem with Efficiency, Fairness, and Accessibility Considerations, Konstantinos G. Zografos



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