Zonal safety analysis (original) (raw)

Zonal Safety Analysis (ZSA) is one of three analytical methods which, taken together, form a (CCA) in aircraft safety engineering under SAE ARP4761. The other two methods are (PRA) and (CMA). Aircraft system safety requires the independence of failure conditions for multiple systems. Independent failures, represented by an AND gate in a fault tree analysis, have a low probability of occurring in the same flight. Common causes result in the loss of independence, which dramatically increases probability of failure. CCA and ZSA are used to find and eliminate or mitigate common causes for multiple failures.