Comparison of techniques for modeling accident progression in dynamic aerospace applications with and without repair

This paper discusses the use of the multiple event tree and single event tree approaches in Probabilistic Risk Assessments for aerospace applications. The issue is how repair can affect the modeling. Four simple examples are presented to show how even a seemingly simple system can become a complex PRA model if the less than optimum approach is used. In cases of repair, it is suggested that the multiple event tree approach is the more appropriate model. In cases of no repair, it is suggested that the single event tree approach is the easier PRA modeling solution.