Failure Condition
Section 06: System Safety & Functional Safety
Definition
A condition having an effect on the aircraft and its occupants, both direct and consequential, caused or contributed to by one or more failures considering flight phase and relevant adverse operational or environmental conditions or external events. A failure condition is not the failure itself but the effect of the failure (or combination of failures) at the aircraft level. Failure conditions are classified by severity and assigned probability objectives accordingly.
Where This Shows Up
The failure condition concept is essential to 14 CFR/CS 25.1309 compliance. The safety assessment process focuses on failure conditions — the effects — rather than on individual failures. A single component failure might contribute to multiple failure conditions, and a single failure condition might require multiple contributing failures. This effects-based approach ensures the analysis captures what matters: the impact on the aircraft and its occupants.
Primary Sources
The primary regulation defining failure condition requirements for transport category aircraft.
Defines failure condition and provides classification criteria.
Related Terms
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