The development of interactive, graphic display devices as interfaces between engineers and computers has opened a new era in man-computer synergetics. Merging the attributes of the digital computer with those of the human in an environment in which there is a freely flowing interchange of information promises great improvements in creativity and productivity.A program developed as a prototype computercentric engineering system at the Lockheed-Georgia Research Laboratory is demonstrating this capability. This program encompasses the aircraft preliminary design process. It provides a capability to evolve rapidly and refine aircraft configurations by graphically and numerically defining aircraft components through interactive, on-line, computer graphic display devices and unique, surface definition programs; to direct the computer in analyses of the components or configurations; and to review the results of the analyses directly on the computer-driven display. Iterations to investigate the effects of modifications to component design, configuration arrangement, missions parameters, or analytical methods are possible at any time throughout the process. A time compression of the preliminary design process of up to ten-to-one is one goal of the program.This paper describes and illustrates the operation of this prototype system and comments on some of the implications of the concept to future engineering processes.