What does the CDI represent in relation to VOR navigation?

The CDI stands for Course Deviation Indicator, which is a crucial component of VOR (VHF Omni-directional Range) navigation systems. This instrument provides pilots with information on how well their aircraft is aligned with the desired flight course.

When flying towards a VOR station, the CDI displays the current course that the aircraft is on relative to the selected course. If the aircraft is on the correct route, the needle will center, indicating that the pilot is on the intended course. If the needle is deflected to either side, it indicates that the aircraft is off course and needs to adjust its heading to return to the correct path.

Recognizing the function of the CDI is essential for pilots during instrument flight as it aids in navigation accuracy, allowing for safe and efficient route management, especially in conditions where visual references might be limited. The relevance of the other terms in the choices does not align with the function of the CDI, as they do not accurately capture the role of this instrument in navigation. Therefore, the nomenclature of Course Deviation Indicator reflects its purpose in guiding pilots to correct their course deviations effectively.