Definition
An HF leg is a path-and-terminator code used in RNAV procedure design that defines a single, complete holding-pattern circuit which begins and ends at a designated fix. The aircraft crosses the fix, flies one full racetrack-shaped holding circuit (outbound turn, outbound leg, inbound turn, inbound leg), and the leg terminates the moment the aircraft crosses the same fix again. Unlike continuous holding, the HF leg is flown once and then the procedure sequences to the next leg.
Plain English
It is one lap around a holding pattern. The aircraft starts at a specific point, flies one full loop, and the loop ends when it returns to that same point — then it moves on to the next part of the procedure.
Context Anchor
Seen in RNAV instrument procedure design and flight-management-system leg descriptions, especially where a procedure uses a holding-pattern-style turn but only one circuit is intended.
Derivation
In ARINC 424 path-and-terminator coding, two-letter codes describe how each leg is flown and what ends it. The 'H' family of codes refers to holding-style legs. The 'F' indicates the leg terminates at a Fix. So 'HF' literally reads as 'Hold, terminating at a Fix' — flown as one complete circuit.
Why Pilots Care
It defines the exact flight path the FMS or autopilot will follow so altitude and timing requirements are met without extra holding.
Analogy
Think of it like being told to drive one full loop around a traffic circle and exit when you reach the same marked exit point again. You are not staying in the circle indefinitely.
Intuition Check
Do not read HF here as high frequency radio. In this context, HF means a hold-style path that ends at a fix after one circuit.
Example Sentence 1
The approach chart includes an HF leg at WAGGS, so the crew briefed flying one full holding circuit before continuing inbound.
Example Sentence 2
After completing the HF leg the aircraft continues on the next coded leg without entering additional turns.