Method for piloting a hybrid helicopter having an airframe maintained at constant incidence by regulating a position of at least one mobile tail unit surface

A method for controlling a hybrid helicopter, the hybrid helicopter having at least one lifting rotor provided with variable pitch blades, the hybrid helicopter having at least one forward-movement propeller provided with blades, the hybrid helicopter having an empennage provided with at least one moveable empennage surface that is designed at least to generate a pitching moment on an airframe of the hybrid helicopter, the hybrid helicopter having at least one empennage actuator for rotating the at least one moveable empennage surface, the method including a stabilized flight phase comprising a rotor adjustment phase including a longitudinal attitude hold step and a rate-of-climb hold step, as well as a propeller adjustment phase including a forward-movement-speed hold step,

• wherein the stabilized flight phase includes an empennage adjustment phase including the following steps:
• determination, using a main sensor, of a current value of a rotor parameter conditioning a current power drawn by the lifting rotor,
• determination, using an estimator, of a current setpoint of the rotor parameter, which is static or a function of a value of at least one monitoring parameter, in which the rotor parameter is a power drawn by the lifting rotor and the current setpoint is a power setpoint, or the rotor parameter is an engine torque transmitted to the lifting rotor and the current setpoint is a torque setpoint,
• adjustment of a position of moveable empennage surface using a deflection controller as a function of the current value and of said the current setpoint.