The models, which are necessary for risk management at designing of complex systems, as a rule, are not described by differential equations. Mainly, the following types of models are used (Vasiliev and Solojentsev, 1978; Solojentsev, 1991; Solojentsev et al., 1999):

scenario model of risk;

structural or graph-models of risk;

logical risk models;

probabilistic risk models;

models of trouble forecasting;

models of testing technology, consisting of procedures and operations;

models of objects description in the form of requirements of technical specifications;

models of expenses of means for decisions and possible damage in the absence of decisions;

models of organizational management in the form of frame networks, providing support of technology and protocols, release of reports and notifications;

models of programs and test reports, represented by tables;

models of states of system in exploitation in the form of the table “Conditions and parameters”.