Escaping microburst with turbulence: Altitude, dive, and pitch guidance strategies

Three escape strategies are compared for microburst encounters during final landing approach: altitude guidance, dive guidance, and pitch guidance. Th e main difference between pitch guidance and the other two strategies is th at pitch guidance immediately attempts to increase altitude at the expense of airspeed, whereas dive and altitude guidances initially trade altitude f or airspeed. We use a full, six-degree-of-freedom, nonlinear, rigid-body ai rcraft model, including the effects of windshear and wind vorticity, and a model of microburst with turbulence. We also model the effect of stall prev ention on the escape path. Two different approaches are used for comparison : 1) In a sample analysis approach, typical samples of the time histories o f various variables are analyzed. 2) In a statistical approach, the probabi lity distribution of the minimum altitude is estimated by the Monte Carlo m ethod when the statistical properties of the microburst parameters are know n. In the sample analysis and statistical approaches, the simulations take into account turbulence in addition to windshear. Both approaches suggest t hat, within the modeling assumptions presented, and in the absence of human factors, altitude and dive guidance with low commanded altitude may provid e better safety than pitch guidance.