How often is a static system leakage check required for an aircraft?

A static system leakage check is crucial for ensuring that an aircraft's static pressure system is functioning correctly. This check is needed to verify that there are no leaks in the static system which could lead to inaccurate instrument readings, particularly in altimeters and vertical speed indicators. Regulations typically require this check to be performed every 12 months to maintain safety and airworthiness standards.

Regular maintenance intervals like this help ensure that any potential issues are caught and addressed before they can lead to more significant problems during flight. Performing this check every 12 months aligns with recommendations from aviation authorities and helps ensure the integrity of crucial flight instruments over time. The emphasis is on periodic checks, rather than checks before every flight or at flight hour milestones, since those would be impractical and unnecessary considering the stability expected in the static system under normal circumstances.