In this paper, we focus on the problem of evaluating the performance of a cable harness for a complex aeronautical system. Indeed, the various studies carried out in recent years on the subjects of crosstalk and modeling of the power harnesses made it possible to put in place of model bricks and tools of simulations. In addition, the measurement of the impedances of certain equipment has highlighted the experimental tools to be used to obtain these values. However, this involved simple equipment (one to two maximum functions of inductive, capacitive or resistive type). Moreover, the development of a simulation tool offers an opportunity to use this simulation process to evaluate in simulation new cables for the harnesses of a harness of a helicopter engine.