The paper presents a simulation model of the hydraulic system of an aircraft containing a block supply with a variable flow pump, the discharge line of which is presented in the form of a certain container with liquid, the modulus of elasticity of which is constant, and a hydraulic accumulator is installed in the discharge line a certain capacity and pre-charge pressure, resistance of the discharge and drain lines. The developed simulation model allows failure situations, such as: violation of the internal and external tightness, changing the parameters of the accumulator, reducing the pressure of zero flow due to a change in the stiffness of the springs of the control spool and the servo piston of the regulator, jamming regulator in an intermediate position, etc. In addition, the model allows you to calculate the heat losses associated both with the aircraft flight mode and with changes in the hydrodynamic parameters of the system in regular and failure modes.