Aircraft control strategies that minimize the hazard of longitudinal flight through microburst wind shear are developed and analyzed, principally using deterministic trajectory optimization and to a lesser extent using classical control. The purpose is to determine the ultimate limits to safe performance in a microburst and develop control strategies that achieve such performance. Several tragic microburst-related accidents have demonstrated the need for improved control strategies.; Over 1,100 optimal trajectories were computed for jet transport and general aviation aircraft flying through idealized and actual microbursts. They were generated using a new Successive Quadratic Programs trajectory optimization algorithm, which directly handles inequality constraints. Qualitative aspects of the best strategies provide a composite picture of good control in a microburst. Variations of the optimal performance with microburst type, intensity, length scale, and location define safe-performance limits.; Control strategies that track glide path best use pitch steering to counteract airspeed variations and maintain constant lift. Throttle control regulates airspeed loosely. In intense headwind/tailwind microbursts, this strategy holds angle of attack at its stall limit when airspeed drops below the 1-g stall limit. Anticipatory throttle control helps achieve safe performance in intense microbursts.; Optimal safe-performance limits show three length-scale regimes. At short length scales, hazards usually associated with gustiness predominate. At intermediate length scales, a degraded ability to maintain flight path and/or vertical velocity sets the limiting microburst intensities for safe performance. At very long microburst length scales, the hazards associated with intense steady winds are the critical safety limits. Performance safety also varies strongly with microburst location.; The safe-performance limits show that both aircraft, if controlled properly, can penetrate some very severe microbursts. Nevertheless, even the best control strategies have their limits. The jet transport safe-performance limits occur at higher microburst intensities than the general aviation limits.; These studies provide guidelines for design and evaluation of practical microburst-encounter control laws. Controllers should replicate the pitch steering and throttle strategies found in the composite picture of good control. Evaluation should include frequency response analysis and comparison of closed-loop safe-performance limits with optimal limits.
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