Plain English Meaning
NAV is a tag used in NOTAMs to flag that the notice is about a navigation aid — for example, a VOR or ILS that is unavailable or working at reduced capability.
Full Definition
In NOTAM usage, NAV is the keyword identifier indicating that a NOTAM concerns navigation aids — ground-based equipment such as VORs, NDBs, DMEs, ILS components, or other electronic navigation facilities that may be out of service, on reduced capability, or otherwise affected.
Context Anchor
Seen in NOTAMs as a category label for notices about navigation equipment or navigation services.
Derivation
Short for 'navigation,' from Latin navigatio, meaning the act of sailing or steering a vessel. In aviation, navigation refers to determining and following a route, so NAV-tagged NOTAMs are about anything affecting the equipment that helps pilots do that.
Why Pilots Care
A NAV NOTAM may mean a navigation aid you planned to use is out of service. If you were counting on a VOR for an approach or enroute fix, you need to know before takeoff so you can plan an alternate route, approach, or method.
Intuition Check
Do not read NAV as a general label for the whole flight plan. In a NOTAM, it specifically points to navigation aids or navigation services affected by the notice.
Example Sentence 1
During preflight, the pilot reviewed the NAV NOTAMs and saw that the destination VOR was out of service.
Example Sentence 2
Pilots check NAV status before departing into instrument conditions.