Zonal Safety Analysis
ZSASection 06: System Safety & Functional Safety
Definition
A safety analysis that examines each zone of the aircraft to identify potential safety concerns arising from the physical installation of systems and equipment. ZSA evaluates whether items from different systems are installed in the same zone in a way that could create common cause failures, interference between systems, or maintenance errors. The analysis considers wire routing, fluid line proximity, equipment mounting, access for maintenance, and the potential for one system's failure to damage adjacent systems (e.g., a leaking hydraulic line damaging adjacent electrical wiring).
Where This Shows Up
ZSA is performed using aircraft zone drawings and installation data. It addresses physical interactions that are not captured by functional safety analyses like FTA and FMEA. For example, an FTA might assume two redundant flight control channels are independent, but a ZSA could reveal that both channels' wiring passes through the same zone, creating a common cause vulnerability from a zone fire or maintenance error.
Primary Sources
Defines ZSA methodology as part of Common Cause Analysis.
Related Terms
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