Abstract: In this paper,output feedback and part of state feedback, pole assignment and singu-lar perturbation method are used to design the multivariable flight control systems for a high per-fonnance aircraft. Based on Porter's research,the method is improved to overcome its shortcom-ings.The item containing 1/g factor is considered.The corresponding analysis expressions,which can be used to adjust controller's parameters in order to reduce the coupiing action in sys-tem and to assign the zeroes and poles of the closed system to meet the design requirements,are also given. The design method provides very fast and essentially decoupled control.

Key words: flight control, decoupling, multivariable control