Collaboration of wake vortex models and sensors in modern avionic systems

Today's airport capacity is severely limited by separation of approaching and to a lesser extent departing aircraft to ensure that following aircraft do not encounter the wake vortex generated by the preceding one. The encounter of wake vortices, especially during take-off and landing, can cause critical or even catastrophic flight situations for the succeeding plane. Historically, the wake vortex separation standards are based on a `worst-case-scenario' assuming calm and still air conditions responsible for a relatively long wake vortex lifetime. They have proven sufficiently safe but are unnecessarily limiting capacity in favourable, even in average weather conditions. Thus a capacity increase brought about by any change in separation rules has at least to preserve (or, given the expected traffic growth, even improve) the current level of safety. Accordingly, wake vortex warning systems have been devised to increase airside capacity and are nearing experimental implementation. The current systems contain a forecasting component based on meteorological conditions and on propagating the vortex evolution. Secondly a sensing system is ensuring the required level of safety. Both the model predictions and the sensing systems each have their advantages but also individual drawbacks. This paper presents a novel approach on collaboration of the wake vortex prediction and the sensing part. A general overview on the wake vortex phenomenon is given and an approach of fusing the wake vortex prediction with wake vortex measurement is shown. By means of examples the major advantages of the collaboration approach are presented. A discussion on implementation constraints of the proposed system closes the paper.