Definition
Ground-based radio navigation aids that transmit signals pilots use to determine their bearing to or from the station. A VOR (Very High Frequency Omnidirectional Range) provides azimuth (direction) information only. A VORTAC is a co-located facility that combines a VOR with a TACAN (Tactical Air Navigation) station, providing both azimuth information for civil aircraft and azimuth-plus-distance information for military and civil aircraft equipped to receive it. For civil pilots, the practical difference is that a VORTAC also provides DME (distance measuring equipment) signals, while a plain VOR does not.
Plain English
Radio stations on the ground that send out signals an aircraft can use to figure out which direction it is from the station. A VOR gives direction only. A VORTAC gives direction plus distance, so a properly equipped aircraft can also tell how far it is from the station.
Context Anchor
Seen when using VOR navigation, checking navigation radios, identifying fixes, following airways, or reading chart symbols for ground-based navigation stations.
Derivation
VOR stands for Very High Frequency Omnidirectional Range — 'omnidirectional' meaning the station radiates usable signals in every direction around itself. VORTAC combines VOR with TACAN (Tactical Air Navigation), a military system that adds distance information. The two were combined into single ground stations so that civil and military aircraft could both use the same facility.
Why Pilots Care
They provide reliable navigation references that form the traditional airway structure and serve as a non-GPS backup.
Analogy
Think of the station like the center of a wheel. The VOR direction lines spread out from it like spokes, and the aircraft can tell which spoke it is on.
Intuition Check
Do not read NAVAID as any general thing that helps with navigation. In this context, it means a specific ground-based radio facility used by aircraft for navigation.
Example Sentence 1
The pilot tuned the VORTAC and used the bearing and distance readouts to confirm the aircraft's position along the airway.
Example Sentence 2
When GPS was unavailable, the crew navigated using the nearest VOR/VORTAC NAVAID.