The cathode ray tube screen will display a plan view of the part outline and defects when using:

• A. A C scan presentation
• B. An A scan presentation
• C. A B scan presentation
• D. Automatic read out equipment

Answer: (A)

The plan view on the CRT comes from a C-scan presentation. In this mode, the transducer is moved over the part (or the data is collected from multiple positions) and the reflections are plotted as coordinates on a two-dimensional map, showing the part outline and defect locations across the surface. This creates a plan view of what’s inside the part.

An A-scan, by contrast, displays a single trace of signal amplitude versus time for one probe position, giving depth information but not a surface map. A B-scan compiles scans along a line into a cross-sectional image, showing a slice through the material rather than a full surface map. Automatic readout equipment is simply data readouts, not a plan view on the CRT.

So, for a plan view of the part outline and defects, the C-scan presentation is used.