A radio navigation system that provides an aircraft with slant-range distance to a ground station, displayed in nautical miles (NM). DME does not give bearing by itself, it only tells you how far you are from the station.
Key characteristics:
- Distance only: Shows range to the station (no left/right guidance).
- Slant-range, not ground range:
The distance is the straight-line distance between the aircraft and the station. At higher altitude and close range, this can read noticeably larger than “distance over the ground.” - Paired with other aids:
- VOR/DME: bearing (VOR) + distance (DME)
- ILS/DME: localizer/glideslope (ILS) + distance (DME)
- TACAN: military system that effectively provides DME-like distance plus bearing.
- Operational use: Supports position fixes, approach segments, holding, and IFR situational awareness.
Application in DCS World
- DCS does not feature a full civilian VOR/DME network like civilian sims, but the concept is directly applicable because:
- TACAN distance readout behaves like DME (distance in NM to the station).
- Many procedures you’d do with DME in real aviation (range checks, “at 10 DME start descent,” holding distances) can be trained using TACAN in DCS.
- Some airfields/nav aids may include DME behavior via mission design or aircraft-specific implementations, but in practice cadets will use TACAN as the DME substitute most of the time.
Cadets should train to interpret DME correctly (especially slant-range effects) and use it for timing, fixes, and approach discipline.