What represents an edge that cannot be seen from a specific position in aircraft drawings?

In aircraft drawings, a medium width hidden view line is used to represent edges or features of an object that are not visible from the current viewpoint. These lines are drawn as a series of dashes and are significant in providing a complete understanding of the component's design without requiring multiple views.

By using hidden view lines, designers can effectively communicate parts of the structure that are obscured in the primary view, allowing engineers and technicians to understand the full geometry of the component. This representation is crucial for proper assembly, maintenance, and inspection of aircraft parts, as it helps visualize the internal or obscured features that are essential for those who work with the aircraft.

On the other hand, dash-dot lines, solid center lines, and thick alternate position lines serve different purposes in technical drawings. Dash-dot lines often indicate symmetry or phantom outlines, while solid center lines represent axes of symmetry or critical positioning references. Thick alternate position lines indicate a different position of an object or feature rather than hidden detail. Therefore, while all these lines have specific roles within technical illustrations, the medium width hidden view line is uniquely designed to depict non-visible edges, making it the correct answer in this context.