Definition
Geographically defined points used in navigation to identify a specific position along a route or procedure. A fix can be established by ground-based navigation aids (such as VOR radials or DME distances), by GPS coordinates, or by the intersection of two such references, and is typically named with a five-letter pronounceable identifier on en route and approach charts.
Plain English
A fix is a named spot in the sky. Pilots use it to report their position, to mark where to turn, or to identify the start or end of a segment of a route or approach.
Context Anchor
Seen on instrument flight plans, en route charts, and instrument approach charts as named points along a route.
Derivation
From the older navigation term 'to fix a position,' meaning to determine exactly where you are. A fix in flight is therefore a point whose location is firmly established and known.
Why Pilots Care
Fixes enable accurate IFR navigation, traffic separation, and compliance with published routes and clearances.
Intuition Check
Fixes does not mean repairs here. In this context, fixes are known positions used for navigation.
Example Sentence 1
ATC instructed the crew to cross the next fix at or above 9,000 feet.
Example Sentence 2
The route was defined by a series of fixes between the departure and arrival airports.