What is the primary function of a DME in air traffic management?

The primary function of a Distance Measuring Equipment (DME) is to determine the distance from the aircraft to a ground station. DME achieves this by measuring the time it takes for a signal sent from the aircraft to reach the ground station and return. By calculating this time interval, it can provide pilots and air traffic controllers with precise distance information, which is crucial for navigation and maintaining safe separation from other aircraft.

Knowledge of the aircraft's distance from the navigation source helps pilots in their approach and departure phases, enhances situational awareness, and aids in operational efficiency. Other functions, like providing altitude information, calculating ground speed, or indicating air traffic levels, are performed by different systems and instruments, which do not fall under the DME's capabilities.