Abstract: This paper studies the characteristics of equilibrium states in the steady flight of an aircraft, analyzes the existing trimmed-method and presents a general method of solving the various equilibrium states of any aircraft. It does work only through aircraft model input and output signals with restrictive condition. Mixture genetic algorithm combined with the genetic algorithm and the simplex algorithm is used to improve the searching process and precision. The result shows that the algorithm has good convergence and steadiness.

Key words: flight control, equilibrium state, flight trimming, genetic algorithm, simplex algorithm