Plain English Meaning

These are airway routes that follow older-style ground radio beacons instead of the more modern VOR stations. On the chart they show up in brown and are named with a color and a number. They mostly exist in places like Alaska where VOR coverage is thin.

Full Definition

Federal airways defined by low frequency and medium frequency non-directional radio beacons (NDBs), shown in brown on IFR en route low altitude charts and identified by a color and number (for example, Amber 1 or Green 3). They form designated routes between NDBs in areas where VOR coverage is limited, primarily in parts of Alaska and a few other remote regions.

Context Anchor

Seen on IFR en route low altitude charts, especially when reviewing routes and older ground- routes.