Montana Department of Transportation


Airport Services

Airway Beacons

The Montana Department of Transportation Aeronautics Division operates and maintains various components of the State and National Airways System. These components include Non-Directional Beacons (NDBs), UNICOM surface-to-air radio systems, and night-time lighted airway beacons.

Non-Directional Beacons
MDT Aeronautics operates and maintains a network of NDBs throughout the state. These are usually on or near general aviation airports. NDBs consist of an antennae array and a transmitter, as well as other electrical support equipment and monitors. NDBs provide signals for aircraft utilizing ADF technology and guidance. NDB/ADF navigation is one of the oldest and most basic types of electronic navigation. It was used routinely as far back as World War II.
UNICOMs are federally approved radio transmitters that are commonly used at airports for communication between pilots and the airport or ground services. Approximately 70 division-owned UNICOMs are located at various airports across the state. Our division provides ownership, maintenance and support for these radios.
Night-time Lighted Airway Beacons
The night-time lighted airway beacon system is unique to the state of Montana. In the 1920s and 1930s, radio navigation for aircraft was virtually non-existent. Instead, early pilots relied upon a system of federally operated lighted airway beacons. Some of these beacons were quite literally bonfires, lighted and stoked by hardy patrons. Electronic bulbs later replaced the bonfires, lighting airway corridors across mountains and plains for pilots to follow at night and during inclimate weather. As technology improved, airway beacons became a thing of the past. Today, Montana is the only state that still utilizes part of this historic network through our rugged western mountains.