For reducing a risk potential of an aircraft, a safety device for the aircraft is provided, said aircraft having a flight control device for flight control of the aircraft based on global position coordinates and/or flight altitude values of the aircraft detected by a sensor apparatus of the flight control device. The safety device comprises a flight altitude detection apparatus configured to detect a current flight altitude of the aircraft independently of the sensor apparatus, a determination apparatus configured to determine whether the current flight altitude of the aircraft detected by the flight altitude detection apparatus exceeds a predetermined maximum altitude, and a rescue apparatus configured to interrupt the flight control of the aircraft when the current flight altitude of the aircraft detected by the flight altitude detection apparatus exceeds the predetermined maximum altitude.