The air turbulence signal is one of the most important disturbances that act during the flight of the aircraft, and therefore, the simulation of atmospheric turbulence is of considerable importance in the evaluation of an aircraft performance in real conditions. Passing a white stochastic sequence through the adequately designed linear filter, the obtained signal at its output will be with a power spectral density very close to the von Karman power spectral density model of air turbulence. The paper presents an analysis of the influence of the filter order and an optimization procedure for filter parameters tuning, in order to obtain a suitable approximation of the von Karman spectra.