Accident cause analysis of complex systems based on safety control functions

State of the art computers have made many technology-based systems so complex that new types of accidents now result from dysfunctional interactions between system components, further adding to the number of accidents resulting from component failure. Other factors, such as management effectiveness and organizational constraints, also must be considered as part of a failure prevention strategy. Conventional event-based analysis methods such as fault trees and event trees cannot be applied to such types of accidents. This paper applies a concept of safety constraints in systems control to the accident cause analysis. The analysis shows the effectiveness of the proposed method for both the retrospective and prospective events