What does the ILD revert to when no glide slope is available?

The correct response indicates that when a glide slope is not available, the Instrument Landing System (ILS) will revert to a non-precision localizer approach. A localizer precision approach refers to an approach where both lateral (horizontal) and vertical (glide slope) guidance is provided. However, in the absence of glide slope information, the approach is downgraded to non-precision, which relies solely on lateral guidance provided by the localizer.

The distinction here is significant: a non-precision localizer approach affords only horizontal direction to align with the runway, lacking the vertical guidance that assists pilots in safely completing the descent to the runway. This shift emphasizes the importance of understanding the limitations and guidance available with different types of instrument approaches in aviation.