What tool is used for the internal inspection of an engine?

• A. Endoscope
• B. Flashlight
• C. Stethoscope
• D. Borescope

Answer: (D)

A borescope is used for internal engine inspection. It’s a slender probe, either rigid or flexible, with light and a camera/viewing tip that you can insert through service ports to peer inside compressor and turbine areas, the combustion chamber, and other hard-to-reach passages. This lets you directly observe wear, cracks, corrosion, foreign object damage, or debris without taking the engine apart, which is essential during overhaul and routine checks.

A flashlight only provides light and no direct view of interior surfaces. A stethoscope listens to sounds to diagnose issues but doesn’t reveal internal conditions. An endoscope exists in medical contexts and some industrial versions exist, but the borescope is specifically designed for the bore and internal passages of engines, offering the right size, optics, and illumination for accurate inspection.