In this paper a passive fault tolerant controller based on nonlinear PID backstepping is proposed for a quadrotor unmanned aerial vehicle. The proposed approach is able to ensure robustness and maintain performance in presence of both actuators faults and parameters changes. The nonlinear PID controller is applied for the problem of trajectories tracking. The proposed approach is compared with the classical backstepping tracking controller. Numerical simulation results are provided to show the effectiveness and the good tracking performance of the proposed approach.