航空公司运营与管理Airline Operations at airports.ppt

5. the optimal turnaround time---analytical methods In order to evaluate the potential impact of schedule changes on flight delays and delay related costs, an analytical model, called the Turnaround Time Allocation (TTA) optimization model is introduced in this section. The objective of this model is to provide airline schedulers with an evaluation tool that can be applied at the stage of schedule planning for different scheduling considerations. Delay development mechanism (1) the arrival delay is shorter than the scheduled buffer time; (2) if the arrival delay is larger than the scheduled buffer time, the resulting departure delay may develop according to one of three scenarios. First, departure delay may develop in a linear form proportional to the amount of arrival delay, no matter how long the arrival delay is. Second, ground handling agents maintain efficient turnaround operations, the level of departure delay will be less than the one of inbound delay. Third, ground operations are further disturbed by the late arrival of inbound aircraft, via late transfer of passengers, late passenger check-in, late baggage connection, or disruptions in ground handling plans. One major responsibility of airline dispatchers at airports is to deliver punctual departures by “operational means”. Ways in which this can be done include: skipping the loading of some cargo or goods that are not urgent, or allocating more resources to speed up aircraft turnaround. The curve slope (m2) after the turnaround buffer time is used to define the “efficiency” of ground services, i.e. the ground handling agents’ capacity to respond to schedule perturbations. The “efficiency” of delay absorption of schedule buffer time is modeled by m1, which is the slope of the left portion of Curve B. The operational efficiency of aircraft turnaround operations in dealing with delays and resource constraints is modeled by m2, which is the slope of the right portion of Curve B. The relationship between