Definition
An RNAV path terminator that defines a leg beginning at a specified fix and continuing on a defined course until the aircraft reaches a specified altitude. The leg ends when the altitude is reached, not at a geographic point. The course is flown until the climb (or descent) target altitude is achieved.
Plain English
A flight path segment that starts at a named point and keeps going on a set heading or track until the aircraft climbs or descends to a chosen altitude. The altitude is what ends the leg, not a place on the map.
Context Anchor
Seen when studying how instrument approach, departure, or missed-approach paths are built and displayed in a flight navigator.
Derivation
In ARINC 424 path terminator coding, the first letter describes the start of the leg and the second describes how it ends. 'F' means the leg starts at a fix; 'A' means it terminates at an altitude. So 'FA' literally reads as 'Fix to Altitude.'
Why Pilots Care
Correct execution ensures the aircraft is at the proper altitude before beginning the next segment of the approach or departure.
Intuition Check
A fix is not something being repaired; here it means a defined position in the procedure. An FA leg does not run from one named position to another named position; it runs from a fix until the specified altitude is reached.
Example Sentence 1
After takeoff, the FA leg required us to track 090° from the departure fix until reaching 2,000 feet before turning on course.
Example Sentence 2
After crossing the fix, the pilot maintained the assigned heading on the FA leg until leveling at the published altitude.