Definition
Ground-based navigation transmitters that broadcast in the Very High Frequency band (108.0–117.95 MHz) and provide pilots with bearing and, in some cases, distance information for en route navigation, approaches, and airway definition. The category includes VOR, VOR/DME, and VORTAC stations, which are depicted on IFR en route charts and form the backbone of the conventional Victor airway system at low altitudes.
Plain English
These are radio stations on the ground that send out signals in a specific frequency range. Pilots tune them in to figure out which direction the station is from the aircraft, and sometimes how far away it is. They are the traditional radio beacons used to fly along charted routes.
Context Anchor
Seen on IFR en route low altitude charts, where navigation facilities are shown so pilots can plan and fly routes using approved radio navigation sources.
Derivation
VHF stands for Very High Frequency, the radio band from 30 to 300 MHz. Aviation navigation aids in this band were chosen because VHF signals travel in straight lines and resist the static and weather interference that plague lower frequencies, making them reliable for navigation but limited to line-of-sight range.
Why Pilots Care
They supply the primary navigation references for low-altitude IFR routes when GPS is unavailable or not authorized.
Grounding Statement
Picture a fixed station on the ground sending out a signal that your aircraft receiver uses like an electronic reference point.
Intuition Check
Do not read radio aids as radios used for talking. Here, radio means a transmitted navigation signal, and aids means facilities that help the aircraft navigate.
Example Sentence 1
The instructor pointed out the VHF radio aids to navigation along the planned route, showing how each VOR defined the next leg of the airway.
Example Sentence 2
During the IFR climb, the crew cross-checked position using two separate VHF radio aids to navigation.