The Royal Air Force policy for microcomputer based training is aimed at solving appropriate and identified training needs: in the most cost-effective way. This paper describes three training aids, all developed in-house, which illustrate this policy in practice. The first is an Air Intercept Trainer which is now in use with the air defence training and operational units: it is a small real-time simulation with student replay facility. The second is a part-task trainer for use in navigation training/instrument interpretation on the RAF's new basic flying trainer; this again responds in real-time to students' inputs and provides immediate feedback and replay facilities. The third aid aims to enhance the quality of classroom instruction by the use of computer-generated controlled animated displays of aircraft technical systems. Finally the paper will argue, through the experience gained, the merits of such in-house development.