Definition
A NOTAM contraction indicating that, at a co-located VOR/TACAN facility (a VORTAC), only the TACAN portion is operating. The VOR component is unavailable, so civilian pilots relying on VOR navigation cannot use the station, while military and civilian aircraft equipped to receive TACAN distance and bearing can still use it.
Plain English
A short code used in NOTAMs to say: at this combined navigation station, the VOR side is out of service. Only the TACAN side is working.
Context Anchor
Seen in NOTAMs or FAA abbreviation lists when a navigation aid has more than one radio-navigation function and only the TACAN side is affected.
Derivation
TAC comes from TACAN (Tactical Air Navigation), a military-developed navigation system. The R indicates a restricted or partial service condition — here, that only the TACAN portion remains. NOTAM contractions are designed to be short so they fit in tightly formatted notices.
Why Pilots Care
Pilots use this information to decide whether their aircraft's navigation receivers can support the planned route or approach.
Intuition Check
Do not read TACR as meaning the entire VOR/TACAN facility is out or changed. It points to the TACAN function only.
Example Sentence 1
During preflight, the pilot saw a NOTAM marked TACR for the VORTAC on their route and chose an alternate navaid for course guidance.
Example Sentence 2
With TACR in effect, the pilot tuned the TACAN receiver instead of the VOR.