Assessment of wake vortex separation distances using the WAVIR toolset

Increases to the capacity of the National Airspace System (NAS), and reduction of delayed and cancelled flights, can be achieved by increasing the landing and takeoff capacity of the runways at the nation's busiest hub airports. NASA and the FAA are evaluating the feasibility of increasing runway capacity through reduced wake vortex separation distances between aircraft in the arrival and departure flows. Traditionally three methods have been used to determine safe wake vortex separation distances: (i) flight test experiments, (ii) historic operational data, and (iii) analytical models. This paper describes the WAVIR toolset, developed by the National Aerospace Laboratory NLR (the Netherlands), for evaluation of wake vortex separation distances. WAVIR is an analytic tool that uses stochastic models for wake vortex generation, wake vortex encounter, aircraft separation, and pilot/aircraft response to an encounter of varying magnitudes. The WAVIR tool provides the ability to evaluate the feasibility of different separation distances between fleets of heterogeneous aircraft under different operational, weather and wind conditions. The approach is applied to evaluate the safety related to current practice single runway arrivals.