An individual trainer for giving students in the radar intercept observer (RIO) schools concentrated practice in procedures for air-to-air intercepts was designed around a programmable graphics terminal with two integral minicomputers and 8k of core memory. The trainer automatically administers practice in computing values of variables in the intercept triangle, and in making the turns required to put the fighter into position for a sidewinder attack. In an initial field trial at the RIO school, Glynco, Georgia, each of 29 students received 10 hours of practice on this trainer. Data for the values of 33 variables were automatically recorded and were analyzed. It was concluded that this form of computer assisted instruction does produce worthwhile gains in fluency of performance and understanding of the intercept problems. (Author)