Definition
Planned or unplanned periods when a VOR or VORTAC ground station is taken out of service, leaving the navigation signal unavailable for use. During a shutdown, any airway, route, or instrument procedure that depends on that station may be unusable, and pilots must use a substitute means of navigation such as another navaid, GPS, or ATC radar vectors.
Plain English
Times when a ground-based navigation station is switched off, so the signal pilots normally rely on isn't there. If your route used that station, you need another way to navigate.
Context Anchor
Seen in instrument procedure and route planning discussions, especially where older ground-based navigation routes are being replaced or supported by other approved navigation methods.
Why Pilots Care
Allows continued safe instrument navigation and prevents route disruptions when primary aids are unavailable.
Analogy
It is like a road closure: the destination may be the same, but the marked path to get there has to change because one of the guide points is no longer usable.
Grounding Statement
A shutdown means the navigation signal from that facility is not available for normal pilot use.
Intuition Check
Do not read “shutdown” as only a brief power-off event. In this context, it can mean a navigation facility has been removed from service temporarily or permanently, and the route system must account for that.
Example Sentence 1
Before the flight, the pilot checked NOTAMs and found a VOR/VORTAC shutdown along the planned route, so she filed an alternate airway using GPS waypoints.
Example Sentence 2
A NOTAM about VOR/VORTAC shutdowns prompted the crew to select an alternate route for the IFR flight.