What type of distance does the DME display?

The Distance Measuring Equipment (DME) provides pilots with a measure of slant range distance in nautical miles from the aircraft to the DME ground station. Slant range is the straight-line distance, or the hypotenuse of a triangle, between the aircraft's altitude and the DME station, hence it is not merely the horizontal distance but includes the vertical component as well. This information is critical for pilots during navigational tasks, as it helps to determine the aircraft's position relative to the DME facility.

Understanding this type of distance is essential in aviation navigation and communication, as it allows pilots to effectively manage their approach and landing phases, ensuring they have accurate data regarding how far they are from their navigation reference point.