A case for the consideration of system related cognitive functions throughout design and development

Modern avionics and digital computing are rapidly advancing engineering fields. However, associated design and development methodologies lag behind these advances. As a result, Man‐Machine Systems (MMS) are increasingly entering service with performances less than, or different from, that required by their specification. In United Kingdom military systems procurement, this performance‐associated problem is strongly related to a gap between the contracted system requirements and the requirements related to the system's “Fitness for Purpose” as determined by the elected Ministry of Defence (MoD) system acceptance authority. “Fitness for Purpose” requirements consider the safe usage of the system, its utility, and its ease of use. Addressing this performance problem requires an understanding of what is being missed in the subject gap and whether what is missing is related to engineering methods or poor consideration of functionality. The problem is based partly on incomplete system specification, specification that emphasizes the physical engineering of the system at the expense of the cognitive functions needed for the skilled operation of the system. Considering these differences, traditional Human Factors (HF) / Ergonomic based techniques, and those of other disciplines related to system design, are becoming increasingly inappropriate for use in the design of new avionics systems. One avenue to promote HF value to design would be to complement systems engineering by the early integration of cognitive functions into the requirements capture processes, both user and system. These cognitive functions should be considered as an integral part of an MMS's functionality and, for convenience, will be termed System Cognitive Functions (SCFs). Advocated through the use of SCFs is a human‐orientated approach to assist the logical and physical SE processes, this to assist in defining system capabilities and expected performance. Suggested is a new emphasis on the early capture of the differences between the specified system performance requirements and the requirements needed to satisfy the “Fitness for Purpose” criteria met at a customer's formal acceptance of the system. These differences are seen as particularly related to MMS management and control, and point toward a need to discover methods suitable for the marriage, and associated trade‐offs, between MMS human‐associated functions and engineered functions. It is argued that the capture and use of SCFs could assist in the knowledgeable adoption of new technologies. © 2000 John Wiley & Sons, Inc. Syst Eng 3:113–127, 2000