Optimal Lateral Escape Maneuvers for Microburst Encounters during Final Approach

摘要

The control and optimization of lateral escape trajectories in a microburst windfield for an aircraft on final approach is discussed. The performance index being minimized is the peak value of altitude drop. The characteristics of open loop extremal solutions for different locations of the microburst were calculated. If a sufficiently large bank angle limit is specified and the center of the microburst is not too far offset from the centerline extension of the approach runway, typically three trajectories can be found that satisfy the first order necessary conditions of optimality. The results bear out that trajectories that feature lateral maneuvering to turn the aircraft away from the microburst center, offer a significant improvement in the escape capability of the aircraft in comparison to a trajectory that passes through the center. In contrast to nonturning escape maneuvers, lateral escape maneuvers often exhibit an initial climb, rather than a descent. It is conjectured that this behavior is a result of optimal energy management. Efforts to develop a closed loop (feedback) guidance scheme that closely approximates the open loop trajectories are described.