Abstract: This paper presents the general principles of knowledge engineering that have led the current emphasis on rule-based expert systems and the corresponding fields of knowledge base and inference machine. Software systems that embody knowledge and apply it skillfully seem capable of equaling or surpassing the performance of individual human expert. It . provides a prospective influences in the concepts and methodologies for engineering structure and promises to make knowledge a valuable industrial commodity.Sample-models of inspection, classification and design for aeronautic structures are given for illustrating the technology.