Definition
A specified geographic point used as a reference during an instrument approach procedure. Approach fixes mark the beginning, transitions, and key decision points of the approach, and are identified by navigation aids, intersections, DME distances, or GPS waypoints.
Plain English
A named point in the sky that pilots use as a marker while flying an instrument approach to a runway. It tells the pilot where they are along the approach and what to do next.
Context Anchor
Seen on instrument approach charts, in navigation equipment, and in controller instructions when setting up to land.
Derivation
From 'approach' (the segment of flight bringing the aircraft toward landing) and 'fix' (a known position, from Latin 'fixus' meaning 'fastened' or 'set in place'). A fix is a position you can pin down with certainty, hence a reliable reference point along the approach.
Why Pilots Care
It signals the exact location to begin final descent, configure the aircraft, and manage timing for a stable approach.
Intuition Check
Do not read fix as “repair.” In aviation, a fix is a known position. An approach fix is a known position used during the approach to an airport.
Example Sentence 1
The pilot crossed the approach fix and began the final descent toward the runway.
Example Sentence 2
ATC cleared the flight direct to the approach fix to begin the ILS procedure.