Definition
A combined navigation reference in which the distance-measuring portion of a military TACAN station is used by civil aircraft equipped with DME. Civil DME receivers cannot use TACAN bearing information, but they can interrogate the TACAN's distance function and receive slant-range distance from the station, just as they would from a standard civil DME.
Plain English
TACAN is a military navigation station that gives both direction and distance. Civil airplanes can't use the direction part, but they can use the distance part with their normal DME equipment. So 'TACAN/DME' means: the airplane is using the distance signal from a TACAN station.
Context Anchor
Seen on aeronautical charts, approach procedures, and navigation discussions where a TACAN facility is providing usable DME distance information.
Derivation
TACAN comes from 'Tactical Air Navigation,' a system developed by the U.S. military in the 1950s. DME stands for 'Distance Measuring Equipment,' the civil equivalent of the distance function. The slash in TACAN/DME simply signals that the two systems share compatible distance signaling, even though the bearing systems differ.
Why Pilots Care
Allows civilian pilots to obtain accurate slant-range distance from a TACAN station for position awareness and navigation without needing separate DME equipment tuned to a different facility.
Grounding Statement
In practical use, TACAN/DME tells you how far you are from that ground station, not necessarily what direction to steer to it.
Intuition Check
Do not assume “TACAN/DME” means a civil aircraft can use all TACAN functions. In most civil cockpits, the useful part is the DME distance.
Example Sentence 1
The approach uses a TACAN/DME station, so we'll get the distance fix from our DME but reference the VOR for course guidance.
Example Sentence 2
The chart symbol for the TACAN/DME confirmed that distance information was available for civil use during the cross-country flight.