Distance measuring equipment uses timed radio pulses to determine the physical distance between an aircraft onboard interrogator and a ground-based transponder. By measuring the delay between sending a signal and receiving the reply, the system calculates the slant range in nautical miles. Pilots rely on this data to track their exact position along an airway or during an instrument approach.
Heard on the job
We're five miles out on the DME, start the descent to minimums.