Definition
A geographic point used for navigation or air traffic control that is not depicted on standard published charts or in official navigation databases. It is typically defined by a controller or pilot using coordinates, a radial and distance from a navaid, or a bearing and distance from a known fix, and exists only for the duration of a specific clearance or flight plan.
Plain English
A navigation point that isn't printed on the charts. It's made up for a particular flight, usually by giving its position relative to something already known, like 'fifteen miles north of this VOR.'
Context Anchor
Seen in instrument flying discussions about user-defined waypoints and manually creating points that are not already available by name in the aircraft navigation system.
Derivation
Unpublished' simply means not printed in official charts or databases. 'Fix' in aviation means a defined geographic position used for navigation — historically called a 'fix' because pilots would 'fix' their position by cross-referencing landmarks or signals.
Why Pilots Care
Allows direct routing or holding at a point not on published airways or procedures, but the pilot must verify terrain and airspace clearance themselves.
Grounding Statement
Picture a point that ATC or a procedure designer can define precisely, but that does not appear on your chart as a labeled waypoint.
Intuition Check
“Fix” does not mean repairing something; in aviation it means a definite position. “Unpublished” does not mean imaginary or informal; it means not shown to the pilot as a normal named chart or database point.
Example Sentence 1
ATC issued a clearance direct to an unpublished airspace fix defined as the 270 radial at 25 DME from the Boise VOR.
Example Sentence 2
Instead of flying to the published fix, the crew used an unpublished airspace fix five miles closer to the airport.