Preliminary System Safety Assessment
Preliminary System Safety Assessment (PSSA) is utilized to assess the system architecture after the Preliminary Aircraft Safety Assessment (PASA) and System-Level Functional Hazard Assessment (SFHA). PSSA is the bridge between system- and item-level safety activities. Through the assessment, system level safety requirements can be allocated to subsystem and item level, which is the core part for implementing the top-down design concept. This chapter provides a detailed introduction to PSSA and explains the determination of the analysis depth, the prerequisite assumptions, and the assessment process of PSSA and the application of Fault Tree Analysis tools. Finally, the application of PSSA to an electrical power system is presented as an example.