Which statement best describes how VT relates to other NDT methods such as UT, RT, and MT?

• A. VT alone provides complete subsurface sizing.
• B. VT has no role in guiding other NDT methods.
• C. VT is the only method needed for all inspections.
• D. VT screens for surface defects and guides subsequent methods; UT/RT/MT may follow to quantify or inspect subsurface features.

Answer: (D)

Visual testing is the frontline assessment that relies on sight to identify surface conditions and defects. It quickly reveals surface flaws, corrosion, misalignment, and surface geometry, and it helps determine where and how to apply additional methods. Because VT shows where problems exist on the surface and how they relate to features, it guides the selection and placement of further NDT techniques. UT, RT, and MT are then used to quantify or inspect subsurface features that VT cannot reliably assess. VT alone cannot size or reveal subsurface defects, so the relationship described—VT screens for surface defects and guides subsequent methods, with UT/RT/MT following as needed—best captures how these methods work together.