A Systems Model of Accidents

摘要

A new model of accidents is proposed based on systems theory. Systems an viewed as interrelated components that are kept in a state of dynamic equilibrium by feedback loops of nformation and control. Accidents result from inadequate control or enforcement of safety-related cor straints on the system. Instead of defining safety management in terms of preventing component failure vents, it is defined as a continuous control task to impose the constraints necessary to limit system behavior to safe changes and adaptations. Accidents can be understood, using this model, in terms of why the centrols that were in place did not prevent or detect maladaptive changes, that is, by identifying the safe y constraints that were violated and determining why the controls were inadequate in enforcing them. This model provides a theoretical foundation for the introduction of unique new types of accident analysis, hazard analysis, risk assessment techniques, approaches to designing performance monitoring and safe y metrics, and accident prevention strategies.