Definition
An ARINC 424 path and terminator leg type that defines a specified course originating at a fix and terminating at a defined along-track distance from that fix. The aircraft flies the published course outbound from the starting fix until the FMS calculates that the specified distance has been covered, at which point the leg ends and the next leg begins.
Plain English
A coded instruction in the flight management system that says: 'Start at this point, fly this exact heading or track, and stop when you have flown a set number of miles.' It defines the path by a course and a distance rather than by a second fix.
Context Anchor
Seen in FAA discussions of path-and-terminator legs and in how instrument procedures are coded for panel navigators.
Derivation
In the ARINC 424 leg-type code, the first letter describes the path and the second letter describes how the leg ends (the terminator). 'F' means the path begins at a fix on a defined course; 'C' means the leg terminates at a specified distance. So 'FC' literally encodes 'Fix-to-distance, flying a Course.'
Why Pilots Care
Knowing the leg type helps pilots understand why the FMS sequences from one waypoint to the next at a particular moment. On an FC leg, the aircraft will turn or transition based on distance flown, not on crossing a named waypoint, which affects situational awareness and monitoring.
Grounding Statement
Picture crossing a named point, flying along the published line for the stated miles, and then beginning the next part of the procedure.
Intuition Check
Do not assume every instrument-procedure leg ends at a named fix. An FC leg starts at a fix, but it ends when the specified distance from that fix is reached.
Example Sentence 1
After crossing the initial fix, the FMS sequenced an FC leg, flying the published course for six miles before turning onto the next segment.
Example Sentence 2
The FC leg ensures the aircraft departs the hold fix on the correct outbound course before turning to join the next segment.