CCA

Common Cause Analysis

A systematic analysis that identifies whether a single fault, event, or environmental condition can cause the simultaneous failure of multiple components that are otherwise nominally independent. Required, in effect, by FAA 25.1707(d) and (i).

Technical detail

Under §25.1707(d), CCA addresses whether physical proximity of independent airplane power sources creates damage-propagation paths that defeat redundancy. Under §25.1707(i), CCA addresses whether the failure of a single mechanical control cable can damage an EWIS component supporting a redundant function.

CCA outputs feed both the certification package and the maintenance program — particularly the Enhanced Zonal Analysis Program (EZAP).

When it matters

Redundant power-source layouts, redundant flight-control runs, and any zone where physical proximity could defeat functional independence.

Related terms

FAA 25.1707 — System Separation Requirements
The Federal Aviation Regulation that requires EWIS to be physically separated and electrically isolated from other EWIS, aircraft systems, fluid lines, control cables, and heated equipment such that no credible failure can produce a hazardous condition.
Enhanced Zonal Analysis Program
A maintenance-program structure that drives zone-by-zone inspection of EWIS, used to ensure that age-related EWIS issues are surfaced before they create hazardous conditions.