The Canadian Defence and Civil Institute of Environmental Medicine (DCIEM), Systems Modelling Group sponsored the development of a new human performance modeling approach based on an Information Processing and Perceptual Control Theory model. The approach combines Hierarchical Goal Analysis with simulation to predict a human "operator loading, performance and error production" versus the classic analytic approach of predicting performance under simulated "task loading". This paper will describe the implementation of the theoretical approach within a task network simulator called the Integrated Performance Modelling Environment (IPME) and discusses its intended use and benefits.