Accident and Incident Analysis Based on the Accident Evolution and Barrier Function ( AEB) Model

Abstract: This contribution presents a model and a description of how to conduct incident and accident analyses using the Accident Evolution and Barrier Function (AEB) method. The method enforces human factor experts and other experts to cooperate in a conjoint process leading to the analysis. An accident is modelled as a sequence of interacting malfunctions and errors in human and technical systems leading to an accident. Coupled with most links in the chain there are possibilities to arrest the evolution through barrier functions (e.g., a physical barrier function) serving to stop the sequence of events. The barrier functions are executed by barrier function systems (e.g., a computer-controlled lock). Organisational systems are analysed in parallel or directly after having modelled an accident evolution. The analysis of an incident involves several steps and issues, such as deciding about when to stop going further back in the chain, in what detail to model and barrier function analysis to eliminate or decrease the risk of another accident. The paper also contains material of interest for analysts using other methods of accident analysis.