Segregation

Section 06: System Safety & Functional Safety

Definition

The physical or functional separation of system elements to prevent a failure, external event, or environmental condition affecting one element from propagating to another. Physical segregation involves routing, mounting, or locating redundant elements in different zones, on different sides of the aircraft, or behind different barriers. Functional segregation involves using different interfaces, different power sources, different buses, or different signal paths. Segregation is a key means of achieving independence between redundant elements.

Where This Shows Up

Segregation is evaluated as part of Common Cause Analysis, particularly in Zonal Safety Analysis (ZSA) and Particular Risk Analysis (PRA). Effective segregation ensures that physical threats (fire, rotor burst, fluid leakage) and zone-level events cannot simultaneously affect redundant system elements.

Primary Sources

SAE ARP4761A — Safety Assessment Guidelines

Evaluates the adequacy of segregation through CCA methods.

Related Terms

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