In engineering systems， challenges such as constrained system inputs， model uncertainties， environmental disturbance inputs， system mutations， or system failures often arise， making traditional qualitative theories like state controllability and observability difficult to apply. This paper describes the issues of traditional system state controllability and reachability through the analysis of model uncertainties. By modeling scenarios such as input constraints in aircraft actuators， additional inputs from environmental disturbances like gusts， system mutations during heavy airdrop or aerospace vehicle separation， and system failures， the paper investigates the controllability and stability determination for systems under these different conditions. On this basis， the paper proposes definitions and determination methods for the engineering consistent controllability of system states and outputs within the same system， and also provides a definition for the engineering consistent observability of system states and outputs. These conclusions are able to unify traditional judgments on system controllability， reachability， and stability， and are analogous to the rapidity and accuracy determinations in classic control. For the development of high-performance aircraft， the paper outlines the analysis and verification requirements for design， wind tunnel， and flight tests. An explanation of engineering consistent controllability is provided through the design results of an actual longitudinal flight.