Accident Precursor Analysis (APA)
Definition - What does Accident Precursor Analysis (APA) mean?
An Accident Precursor Analysis (APA) involves the systematic means of analyzing accident precursors to improve the understanding of overall system risk.
Accident precursors are events that must occur in order for an accident to happen within a given period. In this case, a precursor is a situation that has some components that lead to an undesirable outcome.
Safeopedia explains Accident Precursor Analysis (APA)
An APA involves the six steps of building a caseload, identifying the anomaly failure mechanism, gathering evidence, grading each anomalous condition, observing trends, and modeling risk. One of the first steps involves the collection of anomaly sources. It also includes screening methods to categorize anomalies with little or severe risk involved. The next step involves extrapolating an anomaly failure mechanism to another situation to assess whether it reoccurs. The step after that involves addressing the collection of relevant data, followed by grading each anomalous condition. The final few steps involve the analysis of trends and observations, as well as an assessment of risk significance to identify vulnerabilities.
The best way to whittle down accident frequencies is to analyze accident precursors before they have contributed to a catastrophic situation. Some of the accident precursor types are near misses, faults, unexpected operational behaviors, reduced maintenance effectiveness, and unexpected effects from worn-out equipment.
APA is used to update a system’s risk models. It also uses off-nominal behavior in a proactive way, which leads to continuity of operations. APA supports a convergence of assessed risk and operated risk. and without this type of analysis, the risk convergence may respond to system failure.