Abstract: Control surface failures will change the aerodynamics of the aircraft and reduce its maneuverability as well as controllability. The traditional path planning methods based on the normal point-mass model have difficulty in generating an optimal and safe trajectory. To characterize the impaired motions accurately, the sideslip angle and the side force caused by failures were introduced into the simplified point-mass model, and post-failure aerodynamics were estimated. To address the problem of declined controllability and maneuverability, the change rates of the control variables were appended to the modified model and penalized in the cost function. Finally, gauss pseudospectral method was applied to optimize the safe trajectory. Numerical results considering aileron and rudder failures showed that equations of motion and the constraints of both states and controls were satisfied while safe and smooth trajectories were achieved.