How is aircraft damage defined?

Aircraft damage is primarily defined as any deformation or degradation of material properties. This definition encompasses a broad range of issues that can affect the safety and performance of the aircraft. It is not limited to superficial issues or changes in appearance; rather, it focuses on how damage affects the structural integrity and functionality of materials used in the aircraft. Deformation could include bending, warping, or any physical change that compromises the robustness of components, while degradation of material properties refers to a decline in strength, ductility, or overall performance characteristics, which could be caused by factors such as fatigue, corrosion, or impact.

Other choices mention aspects that may indicate damage but do not fully encapsulate the definition. For instance, an increase in weight or size may not necessarily indicate actual damage to the aircraft's materials or structure, as it could also stem from added equipment or modifications. Similarly, a scratch or dent on the surface may be superficial and not reflective of the underlying material's properties. Lastly, changes in engine performance could suggest operational issues, but they do not directly correlate to the physical state of materials used in the airframe itself. The focus on material properties in the context of damage is critical for determining whether an aircraft remains airworthy and safe for operation.