Optimization of aircraft spin recovery maneuvers

In this paper, the problem of aircraft spin recovery is solved as a trajectory optimization problem using direct multiple shooting method with time and altitude-loss as cost functions to be minimized. A stable oscillatory spin state is chosen as the initial condition and the optimal control inputs required to transfer the aircraft to a steady level-flight trim state are determined. Optimal spin recovery simulations are carried out with scaled bounds of control inputs to determine their effectiveness and feasibility for recovery in the case of total control failures. It is shown that spin recovery is feasible in the case of aileron failure, and only arresting of yaw-rate is possible in the case of rudder and throttle failures. Optimal spin recovery simulations are also carried out to determine the effects of wind and aerodynamic forces. It is found that spin recovery solutions are sensitive to initial conditions in the presence of wind, and increase of lift and decrease of drag reduce the altitude-loss of the maneuver.