Primary flight controls for controlling main and/pr tail rotor controls of helicopters, said primary flight controls comprising: - hydraulic servo actuators of the main and/or tail rotor controls, - Fly-By-Wire and/or of Fly-by-light controls comprising at least one control stick to be handled by at least one pilot, said Fly-By-Wire and/or of Fly-by-light controls commanding the position of the hydraulic servo actuators towards said main and/or tail rotor controls, - an electro-mechanical interface arranged between any of Fly-By-Wire and/or of Fly-by-light controls and said hydraulic servo actuators, said electro-mechanical interface for each of said main and/or tail rotor controls comprising: • at least one electro motor, and • mechanical linkages connecting the at least one electro motor to the hydraulic servo actuators - at least one flight control computer connected to said at least one control stick, said at least one flight control computer preparing and transferring electric signals to said at least one electro motor, and characterized in that for each of the main and/or tail rotor controls there is provided one of the hydraulic servo actuators, connected by one of the mechanical linkages to said at least one electro motor, said one hydraulic servo actuator, being of the type having the one mechanical linkage connected to a control valve as an actuator input of said one hydraulic servo actuator and to an actuator output of said one hydraulic servo actuator, said one mechanical linkage comprising first push and pull rods that connect said actuator input to a motor output of said at least one electro motor, and said one mechanical linkage comprising second push and pull rods that connect said actuator output to the motor output of said at least one electro motor, the at least one electro motor being directly linked to the mechanical linkage, wherein an angular position of a rotor of said at least one electro motor corresponds to an associated position of said one mechanical linkage, and the torque delivered by said at least one electro motor to the hydraulic servo actuator being related to the power consumption of said at least one electro motor. - hydraulic servo actuators of the main and/or tail rotor controls, - Fly-By-Wire and/or of Fly-by-light controls comprising at least one control stick to be handled by at least one pilot, said Fly-By-Wire and/or of Fly-by-light controls commanding the position of the hydraulic servo actuators towards said main and/or tail rotor controls, - an electro-mechanical interface arranged between any of Fly-By-Wire and/or of Fly-by-light controls and said hydraulic servo actuators, said electro-mechanical interface for each of said main and/or tail rotor controls comprising: • at least one electro motor, and • mechanical linkages connecting the at least one electro motor to the hydraulic servo actuators • at least one electro motor, and • mechanical linkages connecting the at least one electro motor to the hydraulic servo actuators - at least one flight control computer connected to said at least one control stick, said at least one flight control computer preparing and transferring electric signals to said at least one electro motor, and