Using absorption areas to improve ATFM

The stochastic nature of air traffic management arises mainly from uncertain operational events. This uncertainty may jeopardize the central flow management unit (CFMU) planning leading to safety problems and sub optimally used capacity. An absorption area is defined as one or several free slots in the planning so that the management of uncertainty is easier. Its aim is to compensate the aircraft uncertainty. The issue is to use the free slots in order to absorb uncertainty, and so not modify the initial planning. Finding the best configuration of the absorption areas corresponds to balancing optimally their size with the available capacity in order to absorb uncertainty and minimize "load loss" (unused capacity). This paper presents the initial results of slot allocation problem incorporating absorption areas: Under some elementary assumptions, the simulations show that, for whatever the rate of uncertainty is, the debit of traffic with absorption areas in slot allocation is always higher than without the absorption areas. A theoretical model is attempted to bring the proof to these empirical results.