Definition
An RNAV path-and-terminator leg type that defines a direct course from the aircraft's present position to a specified fix. The leg has no defined starting point; it begins wherever the aircraft happens to be when the leg becomes active and ends at the named fix. The flight management system (FMS) computes the track in real time based on current position.
Plain English
A path in the procedure that simply says: from wherever you are right now, fly straight to this point. The starting place isn't fixed — only the ending place is.
Context Anchor
Seen in instrument procedure coding and on GPS or flight management system route legs during departures, arrivals, approaches, and missed approaches.
Derivation
The name describes the behaviour: the aircraft proceeds 'direct to' a named 'fix.' The 'leg' is the segment of the procedure between two points. No deeper origin is needed — the term is built from operational language.
Why Pilots Care
It enables efficient, flexible routing that shortens paths and reduces pilot workload during instrument procedures.
Intuition Check
Fix does not mean repair here; it means a known navigation point. Leg does not mean a body part; it means one segment of the procedure. Direct does not mean any route you choose; it means the system is guiding the aircraft to the specified fix.
Example Sentence 1
After the missed approach point, the procedure used a DF leg to send the aircraft direct to the holding fix.
Example Sentence 2
The STAR ended with a DF leg to the metering fix before joining the arrival.