Definition
A waypoint type used in RNAV procedures that requires the aircraft to begin its turn before reaching the waypoint, so that the new course is intercepted smoothly without overshooting. The turn is anticipated based on aircraft speed and the angle of the course change.
Plain English
A point on a route where you start turning a little early, so you roll out neatly on the next leg instead of flying past the point and then turning.
Context Anchor
Seen in RNAV departure procedures and navigation database coding to show how a route point is meant to be flown.
Derivation
The name describes the action: the aircraft 'flies by' the waypoint rather than directly over it. The turn is started early so the path passes near the point on the way to the next leg.
Why Pilots Care
It produces predictable, comfortable course changes with minimal overshoot and keeps the aircraft on the protected route.
Intuition Check
Fly-by does not mean a low pass or sightseeing pass here. It means a route point where the turn may begin before the aircraft reaches the point.
Example Sentence 1
Most waypoints on the RNAV departure were fly-by, so the autopilot began each turn slightly before reaching them.
Example Sentence 2
Because the waypoint is coded FB rather than fly-over, the autopilot rolls into the turn before the fix and captures the next track cleanly.