What is line-of-sight in VT?

• A. The observer's direct viewing path from eye to surface.
• B. A route for sending signals.
• C. A line on a blueprint.
• D. A method of lighting.

Answer: (A)

In VT, line-of-sight is the observer’s direct viewing path from the eye to the surface being inspected — an unobstructed straight line along which you can see the surface clearly. This matters because visual testing relies on detecting surface features and flaws, and any blockage, glare, or awkward angle breaks that direct path, making flaws hidden or indistinct. Practically, inspectors reposition themselves and adjust lighting to restore a clear line-of-sight, ensuring the area can be observed without obstructions. The other choices describe a signaling route, a line on a blueprint, or a lighting method, which aren’t what line-of-sight refers to in VT.