Optimization of high angle-of-attack approach to landing trajectories

The use of thrust vectoring technologies for performing extremely short takeoff and landing (ESTOL) operations was recently successfully demonstrated in a series of flight experiments involving an X-31 aircraft. The study presented herein builds on these ESTOL developments. More specifically, the main goal of the present study is to shape high angle-of-attack approach trajectories in such a way that starting at a given altitude and speed, the down-range distance to the runway threshold is minimized. In other words, the steepest approach possible is explored. The approach-to-landing problem is formulated as an optimal control problem and solved numerically, using a rigid-body model of a thrust-vectored version of an F-16 fighter aircraft. The employed numerical method, collocation with non-linear programming, proves well suited for solving this problem.