The Landing Craft, Air Cushion (LCAC) vehicle is a Naval hovercraft that operates in both a sea and terrain environment. Riding on a 5 foot pressurized cushion of air contained by a skirt system, the craft performance is determined by the nature of the terrain beneath it. The LCAC Full Mission Trainer, produced by Hughes Simulation System, Inc., simulates the craft performance over undulating ground and obstructions on the ground. This paper presents how the terrain database is generated and how the craft cushion dynamics is modeled. A discussion of how the modeling of the craft cushion dynamics uses escape areas between the skirt bottom and the ground, and volumes of air within the cushion to determine airflow and cushion pressures is presented. The coefficient of friction implementation for the type of terrain is also discussed.