Definition
A ground-based navigation facility where a VOR (VHF Omnidirectional Range) station and a TACAN (Tactical Air Navigation) station are installed together at the same site, sharing a common location and antenna structure. The VOR portion provides civil aircraft with magnetic bearing information, while the TACAN portion provides military aircraft with both bearing and distance information. Civil aircraft use the VOR for bearing and the distance-measuring component of the TACAN for DME range information.
Plain English
A navigation station on the ground that combines two systems—one used by civilian pilots and one used by the military—so both can use the same site. Civilian pilots get direction information from the VOR part and distance information from the TACAN part.
Context Anchor
Seen in FAA abbreviations, navigation facility listings, charts, and notices about navigation aid status or outages.
Derivation
The name is a blend: V from VOR and TAC from TACAN, joined to show that the two stations share one site. "Collocated" comes from Latin com- (together) and locare (to place)—literally "placed together."
Why Pilots Care
Allows aircraft equipped with either VOR or TACAN receivers to obtain reliable navigation data from the same transmitter location.
Intuition Check
Do not read “collocated” as merely nearby. Here it means the VOR and TACAN are installed at the same navigation site and identified as a combined facility.
Example Sentence 1
The pilot identified the navaid on the chart as a VTAC and tuned the VOR frequency to receive both bearing and DME information.
Example Sentence 2
VTAC facilities are commonly used near military airfields where both civil and tactical navigation are required.