Aviation

Engines-Damage to the compressor, combustion chamber and junction of high and low pressure turbines in the core engine; aircraft engines work in high temperature, high pressure and high speed environment, so fatigue damage and failure also occur in high temperature, high pressure and high speed parts, which are not easy to disassemble and cannot be directly visually inspected. Therefore, the inspection and monitoring of these parts must rely on borescope inspection technology. (Cracks and damage of blades, the size of the gap between blades and casing, etc.)

Case
Blade cracks usually appear as jagged, thin, black lines with sharp ends. The shape of the cracks will not change when the light intensity or angle is changed, and they will show characteristics such as depth and shadow. The continuous expansion of the cracks will eventually lead to the fracture of the components due to aging.

Notch A sharp surface depression at a corner or end caused by pressure or impact from a sharp-edged foreign object. Notches can cause stress concentration and lead to cracking. Usually, notches on compressor blades can cause blade fracture.

A depression in a smooth surface caused by pressure or impact from a blunt, smooth external object.

Bending refers to a change in the shape or profile of a blade, usually as a result of forces acting on one side.