Implication of Variability in Airport Surface Operationson 4-D Trajectory Planning

摘要

A principal theme of future traffic management is the use of planned four-dimensional trajectories (4DTs) for airborne and surface operations at busy airports. In contrast to autopilots following airborne 4DTs, human pilots will continue to manually control the movement of aircraft on the ground. The resulting variability in compliance with planned surface trajectories will have a significant impact on optimal surface planning systems. This paper first explores, parametrically, the relationship between surface trajectory compliance and elements of surface traffic management operational concepts, such as how frequently aircraft trajectories may be re-planned and how far in advance plans must be frozen. Flexibility similar to current operations must be preserved to maintain capacity in the presence of uncertainty. Second, the paper presents examples of the variability currently observed in the movements of aircraft on the airport surface, as an initial bound on the compliance errors that may be expected. Implications of this variability for future surface traffic management concepts are described. Variability creates a tradeoff between trajectories being feasible and efficient, which motivates re-planning trajectories frequently and providing only partial, immediate clearances to aircraft on the surface. Interoperability with airborne 4DT planning systems will require longer planned windows for coordinated events (e.g., takeoff) where the surface planning system may re-plan frequently, moving scheduled times within those frozen windows.