Abstract: In this paper, the lateral flight control system is designed in INA methodology. The result of simulation shows that the lateral controler designed for H= 10 000 metres, Ma = 0.9 can be used in the situation of H= 10 000 metres, Ma=1.5. Finally, robust analysis is done in robust INA methodology, which shows that the design enhances the admissible bound of the model error. All data are calculated by IBM PC computer. Gershgorin bands, Ostrowski bands and robust Gershgorin bands, robust Ostrowski bands are drawn by MP 1000 drawing instrument.

Key words: diagonal dominance, robust, roust diagonal dominance