Approach guidance in a downburst

Abstract

We present a nonlinear feedback law for safe aircraft penetration through downbursts on landing approach. It is based on following a nominal approach path relative to the ground, subject to a minimum airspeed constraint. The guidance design uses a point-mass aircraft model and considers the flight path to be in the vertical plane. We modify the slack variable transformation method to handle the airspeed constraint and apply the nonlinear dynamic inversion technique for the guidance law synthesis. Nonlinear numerical simulation results are presented for three different downburst histories. The main features of the proposed guidance logic are normal behavior when there is no wind, tracking of the nominal path in the presence of downbursts, and insensitivity to different downburst models. Piloting implications and other aspects of landing approach in downbursts are discussed.