A previously developed man-machine model which is capable of simulating closed man-machine systems operated by crews of from 4 to 20 members was substantially modified so as to allow its use for system reliability and system availability predictive purposes. The resultant new model is capable of generating new system availability and reliability measures based on human and equipment performance resulting from the computer simulation runs. A description of the revised computer model including the changes is presented, together with the model flowchart and user information. The degree of success in producing rational output achieved during a set of basic runs using the revised model and program is discussed.