This paper was originally presented at the 56th Military Operations Research Symposium, sponsored by the Military Operations Research Society at the U.S. Naval Postgraduate School, Monterey, California, in June 1988. Its authors examine the simulation architecture that intelligence and operations analysts at RAND developed to evaluate candidates for the Army's attack helicopter fleet in a force-on-force analysis. They present the Cartographic Analysis and Geographic Information System (CAGIS), a supplement to the JANUS model. CAGIS is designed to closely analyze rotorcrafts' vulnerability and chances for survival and describe how this technology was applied specifically to the Light Helicopter Experimental study. The authors then explore the advantages to both intelligence and operations of integrating a threat air defense system into the hierarchy of models and conclude that CAGIS is the key to achieving this integration.