The System Safety Assessment is the final part of the complete Safety Assessment Process which establishes aircraft component (equipment) safety objectives and demonstrates compliance with FAR/JAA 25.1309 and other safety related requirements. The complete Safety Assessment Process begins with a functional hazard assessment (FHA), is normally followed by a qualitative preliminary system safety assessment (PSSA) and ends with the quantitative SSA.

Simply put, the SSA is a systematic, comprehensive evaluation of your equipment, as implemented on-aircraft, to show that the safety objectives from the FHA have been met. In more detail, the SSA is usually based on PSSA analyses and uses quantitative results from Failure Mode and Effects Analyses and/or Summary (FMEA and/or FMES) in support of event driven fault tree analyses (FTA) to show that the probability of the functional hazard (or, fault condition) occurring during flight is less than the maximum value established as the safety objective (in the FHA).