Which event is defined as "substantial damage" according to NTSB Part 830?

The event defined as "substantial damage" under NTSB Part 830 refers to a failure of a component that affects performance. This is because substantial damage signifies that an aircraft has sustained significant harm that could affect its operational integrity, safety, or structural soundness, especially in terms of performance.

This type of damage typically involves critical systems or components that, if they fail, could compromise the aircraft's ability to fly safely. Such definitions aim to ensure that any event leading to performance impairment is reported and investigated, highlighting the importance of understanding aircraft functionality and safety.

In contrast, the other options do not align with the NTSB's definition of substantial damage. Minor body damage, surface paint scratches, and electrical systems failure (depending on severity) do not necessarily indicate a serious degradation of aircraft performance or safety. Therefore, they do not meet the criteria set for substantial damage as outlined by the NTSB.