How is a major change defined?

A major change is defined by how it influences the airworthiness of an aircraft. This definition focuses on the safety and operational integrity of the aircraft, indicating that any modifications that could potentially impact safety standards or performance metrics constitute a major change.

In this context, when airworthiness is affected, it implies that the structural, performance, or operational characteristics of the aircraft have undergone significant alteration, warranting thorough evaluation and possibly new certification processes. This aligns with regulatory frameworks that ensure aircraft remain safe and compliant following modifications.

While other options introduce important concepts related to airworthiness and certification, they do not encapsulate the essence of what constitutes a major change. Simply using a different airworthiness standard, for example, does not automatically indicate a major change unless it significantly impacts the aircraft's operation or safety. Similarly, identifying the applicant as the type certification holder or noting that a part has been replaced does not inherently reflect the broader implications of the modification on airworthiness. The critical factor is the effect on the aircraft’s overall compliance with safety regulations, which directly supports the selection of the correct answer.