The paper presents the results of mathematical modeling and experimental research of the dynamic characteristics of the prototype of aircraft hybrid electrohydraulic steering actuator with combined speed control. The mathematical modeling of dual-mode electrohydraulic actuator was performed in the MatLab Simulink and the experimental research was carried out at the control systems test-rig in Central Aerohydrodynamic Institute. The main goal of the experimental research was to determine the output characteristics of actuator, among them static (speed and mechanical) and dynamic (bode-diagrams, transients responses and dynamic stiffness) in the backup (autonomous) and main modes of its operation, including when the actuator was under load.