Definition
A path-and-terminator leg type used in RNAV procedure coding that defines a specified magnetic course flown to a named fix that ends the leg. The leg has a defined course and a defined endpoint, but the starting point is wherever the previous leg leaves the aircraft. The flight management system steers the aircraft onto the published course and tracks it until the terminating fix is reached.
Plain English
A coded segment of an instrument procedure that tells the aircraft: 'Fly this exact course until you reach this named point, then the leg is finished.' Where you start the leg doesn't matter — the course and the endpoint do.
Context Anchor
Seen in RNAV and GPS instrument procedures, flight management systems, and procedure-leg descriptions for approaches, departures, and arrivals.
Derivation
The two-letter codes used for RNAV leg types describe the leg in shorthand: the first letter is the path, the second is the terminator (what ends the leg). 'CF' means Course (the path) to a Fix (the terminator). Once you know the pattern, every leg type in the family reads the same way.
Why Pilots Care
Provides precise lateral guidance to a waypoint without dependence on a ground station directly ahead of the aircraft.
Intuition Check
Course does not mean a school class or a general plan here; it means the intended path over the ground. A CF leg does not mean reach the fix by any route—it means follow the specified course until the fix.
Example Sentence 1
After the initial climb, the SID coded a CF leg to WILBY, so the FMS turned us onto the published course and tracked it until we crossed the fix.
Example Sentence 2
The approach plate showed a CF leg that brought the airplane straight to the final approach fix.