paper presents an indirect adaptive robust control scheme for time  varying plant in the presence of the modeling error. The robustness is achieved by using a normalizing identification error signal in combination with a dead zone and aprojection algorithm in the adaptive law. This modified algorithm is used to estimate the controller parameters so that the closed loop plant will track a certain desired performance closely in some sense and the plant input and output will remain bounded for all time. The proposed adaptive control algorithm is used to control the behavior of an aircraft system in which a good behavior is  obtained. A comparison between the ordinary projection algorithm and the proposed adaptive algorithm in controlling the aircraft system is carried out. The simulation results indicate the effectiveness of the proposed adaptive control algorithm.