AIM Text
- A VORTAC is a facility consisting of two components, VOR and TACAN, which provides three individual services: VOR azimuth, TACAN azimuth and TACAN distance (DME) at one site. Although consisting of more than one component, incorporating more than one operating frequency, and using more than one antenna system, a VORTAC is considered to be a unified navigational aid. Both components of a VORTAC are envisioned as operating simultaneously and providing the three services at all times.
- Transmitted signals of VOR and TACAN are each identified by three-letter code transmission and are interlocked so that pilots using VOR azimuth with TACAN distance can be assured that both signals being received are definitely from the same ground station. The frequency channels of the VOR and the TACAN at each VORTAC facility are “paired” in accordance with a national plan to simplify airborne operation.
Source: FAA Aeronautical Information Manual · current edition · paragraph 1-1-6.
The short answer
This AIM section is FAA advisory guidance describing a VORTAC as a single navigational aid combining a VOR and a TACAN at one site, delivering three services: VOR azimuth, TACAN azimuth, and TACAN distance (DME). Their frequency channels are paired under a national plan and interlocked so paired signals come from the same ground station, supporting VOR/DME-based navigation under 14 CFR Part 91.
Research Notes
Common Questions
What three services does a VORTAC provide?
Per the AIM, a VORTAC provides three individual services at one site: VOR azimuth, TACAN azimuth, and TACAN distance (DME). Though it uses more than one component, frequency, and antenna, it is treated as a unified navigational aid with both components operating simultaneously at all times.
How do I know the VOR and DME signals are from the same station?
The AIM notes that VOR and TACAN signals are each identified by a three-letter code transmission and are interlocked, so a pilot using VOR azimuth with TACAN distance can be assured both received signals are definitely from the same ground station. The frequency channels are paired per a national plan.
Why are VORTAC frequencies paired?
The AIM states the VOR and TACAN frequency channels at each VORTAC are paired in accordance with a national plan to simplify airborne operation, letting receivers tie azimuth and distance to a common source.