What is the primary functionality of Distance Measuring Equipment (DME)?

The primary functionality of Distance Measuring Equipment (DME) is to provide accurate distance information to a designated VOR (VHF Omnidirectional Range) station or airport. DME works by measuring the time it takes for a radio signal to travel from the aircraft to the DME ground station and back. By calculating this time and considering the speed of light, the DME displays the distance, typically in nautical miles, to the pilot. This information is essential for navigation, helping pilots understand their position relative to waypoints and ensuring they are on the correct flight path.

While altitude measuring equipment is vital in aviation, DME does not measure altitude above sea level. Similarly, while DME can be a part of air traffic control systems, its primary purpose is not direct control of air traffic but rather aiding pilots in navigation by establishing distance references. DME also does not compute flight time to a destination, as that calculation depends on aircraft speed and other variables, not solely on distance measurements. Therefore, the correct understanding of DME's role emphasizes its focus on providing navigational distance information.