a method and apparatus is provided for estimating the mean pressure in a compressible fluid strut . a database is employed containing values for mean pressure variation corresponding to a specific combination of motor speed and flow demand , and may also account for strut temperature . the flow demand and the speed of the motor are determined , and the mean variation corresponding to the determined combination of motor speed and flow demand is selected . the estimation of strut mean pressure is updated with the selected mean pressure variation . in this way , costly pressure sensors are eliminated as well as the complicated control algorithms which are used therewith .