What is the primary purpose of performing a borescope inspection during a turbine engine overhaul?

• A. Visually inspect internal hot-section and auxiliary passages for cracks, deformation, deposits, or obstructions without full disassembly.
• B. To measure blade tip clearance with high precision.
• C. To replace hot-section components.
• D. To test fuel control unit operation.

Answer: (A)

Borescope inspection provides a non-destructive visual view of the engine’s internal hot-section and auxiliary passages, letting you look for cracks, deformation, deposits, or obstructions without fully disassembling the engine. This quick, targeted check is essential during overhaul because it reveals potential trouble areas that might require regrouping inspection, repair, or part replacement before proceeding further. It also helps verify cleanliness and condition early in the teardown or after reassembly, reducing the risk of overlooking hidden damage. While useful, a borescope won’t give precise measurements like blade tip clearance, nor does it directly replace component replacement or functional tests such as the fuel control unit operation.