Definition
A type of flight path segment used in area navigation (RNAV) and required navigation performance (RNP) procedures, defined as a great-circle path between two specified fixes. The aircraft's flight management system flies directly from one named waypoint to the next along this fixed, predictable course.
Plain English
A straight-line course between two named points on a navigation chart, flown automatically by the aircraft's navigation system.
Context Anchor
Seen on GPS and flight management system procedure legs, especially on instrument approaches, departures, and arrivals.
Derivation
From 'track' (the path along the ground that the aircraft follows) and 'fix' (a specifically named navigation point with known coordinates). The name describes exactly what it is: a track that runs from one fix to another fix.
Why Pilots Care
Ensures accurate execution of instrument procedures by following the designed track to the next fix.
Analogy
It is like drawing a line on a map from one marked point to another and following that line, rather than just aiming generally toward the second point.
Intuition Check
Track does not mean simply watching something, and fix does not mean repairing something. Here, track means the aircraft’s path over the ground, and fix means the named point where the leg ends.
Example Sentence 1
Most of the legs on this RNAV approach are track-to-fix segments, so the autopilot will follow the charted path precisely between each waypoint.
Example Sentence 2
During the flight, the FMS transitioned to a Track-To-Fix segment after passing the previous waypoint.