Probabilistic Analysis of Wake Vortex Hazards for Landing Aircraft Using Multilateration Data

Wake vortices are a safety hazard to landing aircraft. A landing aircraft that encounters a wake may roll, resulting in a fatal crash if the roll is severe enough and/or if the aircraft is low enough to the ground. Therefore, aircraft are separated by a sufficient distance to ensure that wakes have time to decay in strength. However, because of the inherent variability in wake behavior and aircraft separation and position, there is still a possibility for a wake encounter. The objective of this paper is to estimate the probability of such encounters. This paper presents a hybrid simulation methodology. The approach is hybrid in the sense that part of the simulation is conducted using a direct data feed of flight-track data, while the other part is obtained by simulation of wake-evolution models. We demonstrate the approach on a one-week sample of flight tracks to predict the frequency of potential wake alerts. In this paper a wake alert is defined to be an event where the trailing aircraft is in a region of space where the wake is likely to be. We show how the results depend on atmospheric conditions and other model parameters. TRB 2007 Annual Meeting CD-ROM Paper revised from original submittal.