Modified Guidance Laws for Escaping a Microburst with Turbulence

This paper introduces Modified Altitudeand DiveGuidance laws for escaping a microburst with turbulence. First, a new safety metric is constructed that quantifies the aircraft upward force capability in a microburst encounter. In the absence of turbulence, the safety factor is shown to be a decreasing function of altitude. This suggests that descending to a low altitude may improve safety in the sense that the aircraft will have more upward force capability to maintain its altitude. In the presence of stochastic turbulence, the safety factor is treated as a random variable and its probability distribution function is analytically approximated as a function of altitude. This approximation allows us to determine the highest safe altitude at which the aircraft may descend, hence avoiding to descend too low. This highest safe altitude is used as the commanded altitude in Modified Altitudeand Dive-Guidance. Monte Carlo simulations show that these Modified Altitudeand DiveGuidance strategies can decrease the probability of minimum altitude being less than a given value without compromising the probability of crash. That is, an aircraft with Modified Altitudeor Dive-Guidance can have a higher recovery altitude without increasing the risk of ground contact or stall.