This paper presents an approach to fault detection and isolation in hybrid systems, with a focus on cyber-physical systems. We utilize hybrid automata to model both continuous and discrete dynamics of an avionics system (aircraft fuel transfer system). The integration of hybrid automata allows for precise representation of normal and faulty operating modes, enabling comprehensive system diagnostics. The proposed method is implemented using Matlab Stateflow environment, demonstrating its effectiveness through practical modeling and analysis of system behaviors under various conditions.