Abstract: A method for authorizing the flight of an aircraft provided with a hybrid power plant having at least one heat engine and at least one electric motor electrically connected to an electrical energy source comprising several electrical accumulators. The method comprises extracting (STP1), while on the ground, an electrical energy or an electrical power to be extracted from the electrical energy source during a predetermined time period and determining (STP2) for the electrical accumulators, respective initial values of an operating parameter, calculating (STP3) an average value from the initial values, determining (STP4) a minimum value from the measured initial values, issuing an authorization when a difference between the average value and the minimum value is less than a threshold and a prohibition when said difference between the average value and the minimum value is greater than or equal to the threshold.

Abstract: An assistance method for assisting a pilot of a single-engined rotary-wing aircraft during a flight phase in autorotation, the aircraft including a hybrid power plant provided with a main engine, with an electric machine, with a main gearbox, and with an electrical energy storage device. The aircraft also includes a main rotor driven by the hybrid power plant. In the method, during a flight, operation of the main engine is monitored in order to detect a failure, in particular by means of a drop in power on the main rotor, then, when a failure of the main engine is detected, the electric machine is controlled to deliver auxiliary power We to the main rotor, making it possible to assist a pilot of the aircraft in performing the flight phase in autorotation following the failure.

Abstract: An assistance method for assisting a pilot of a single-engined rotary-wing aircraft during a flight phase in autorotation, the aircraft including a hybrid power plant provided with a main engine, with an electric machine, with a main gearbox, and with an electrical energy storage device. The aircraft also includes a main rotor driven by the hybrid power plant. In the method, during a flight, operation of the main engine is monitored in order to detect a failure, in particular by means of a drop in power on the main rotor, then, when a failure of the main engine is detected, the electric machine is controlled to deliver auxiliary power We to the main rotor, making it possible to assist a pilot of the aircraft in performing the flight phase in autorotation following the failure.