Cascading Effects

Section 06: System Safety & Functional Safety

Definition

Failure effects that propagate from one system or function to other systems or functions through physical, electrical, logical, or functional interfaces. A cascading effect occurs when a failure in one system causes degradation or failure in another system that is not directly related, through shared resources (power, cooling, data buses), physical proximity, or functional dependencies. Cascading effects can amplify the severity of a failure condition beyond what would be expected from the initial failure alone.

Where This Shows Up

Identification and prevention of cascading effects is a key part of system safety assessment. The FHA and PSSA must consider not just the direct effects of failures but also their cascading effects on other systems. Interface analysis, FMEA with propagation assessment, and common cause analysis all contribute to identifying cascading effects. Design mitigations include isolation, circuit protection, and interface monitoring.

Primary Sources

SAE ARP4761A — Safety Assessment Guidelines

Addresses cascading effects as part of the failure effects analysis methodology.

AC 25.1309-1A — System Design and AnalysisFAA

Requires consideration of cascading effects in the system safety assessment.

Related Terms

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