This paper analyzes the methodology used for scenario development as learned from the Firefinder Radar Trainer. First, an overall concept of the operational and maintenance trainer is given with special emphasis on the scenario training package. The training effectiveness of the system is demonstrated by reviewing the transfer of knowledge tests conducted with the actual system. The management of the scenario data base is described, stressing the use of the Chief Programmer Concept, the reuseability of the data elements, and the adherance to an effective configuration control plan. The characterization of three levels of training complexity as designed in the scenarios is also given. Next, several training schemes are suggested that make the maintenance trainer a cost-effective device. Emphasized are special CAI/CMI techniques used to transform the simulator into an effective trainer.