Instructional simulation is a type of computer assisted instruction that is effective for teaching dynamic skills. Control of instructional simulation may be fully automated (computer control), assigned to learners (learner controlled instruction), or control may be shared between computer and learner (learner control with advisement). The efficiency of these three mechanisms is examined for control of task difficulty, sequence of instructional activities, and pace (time on each activity). The efficiency of control mechanisms is partially determined by the characteristics of the criterion task and the learners' prior knowledge of the subject matter. An instructional simulation that teaches subjects to interpret an aviation display was developed to examine the effects of control mechanisms during the acquisition of a dynamic skill. Results of a pre-experiment and experiment 1 demonstrated that learners' strategies and time on task varied as a function of type of control over task difficulty, and that learners may not be able to effectively control sequence and pace when the subject matter is unfamiliar. Experiment 2 will investigate control of sequence and pace. (16 references) (Author/DB)