This paper discusses some of the problems experienced by operational users in their efforts to obtain maximum training benefit from Advanced Flight Simulators. The major shortcomings of simulation training identified here are not the result of state-of-the-art technology limitations. In fact, many of the training difficulties encountered by simulator users today may have been avoided if greater attention had been given to defining Mission and Task Requirements during simulator design. This suggested emphasis on Mission indicates a change of mind-set is needed that focuses on explicit operational requirements as well as the more conventional technical approach. After analysis of typical simulator training problems, it is concluded that simulation training could benefit substantially through greater consideration to front-end analysis during simulator design, and by providing training personnel with well designed instructional programs that includes an objective Performance Measurement System.