The present disclosure pertains to a multi-rotor unmanned aerial vehicle (UAV). Aspects of the present disclosure provide a UAV that includes at least four arms, each configured with a co-axial pair of contra rotating propellers, wherein each propeller has capability of rotating reversibly with associated reversal of direction of thrust, and an autopilot control system that controls rotational direction and speed of the at least four co-axial pairs of propellers to maintain yaw stability, roll stability and pitch stability of the UAV, wherein in an event of failure of any one co-axial pair out of the at least four co-axial pairs of propellers, the autopilot control system reverses direction of rotation and thereby direction of thrust of at least one propeller of any functional pair.