Definition
A path and terminator leg type used in RNAV procedure coding in which the aircraft flies a specified heading until it intercepts the next leg of the procedure. The 'V' designates that the path is flown as a heading (through the air mass, not corrected for wind), and the 'I' designates that the leg terminates upon interception of the following leg's course or track.
Plain English
A coded instruction in an instrument procedure that tells the aircraft to fly a given heading and keep flying it until it crosses and joins the next segment of the route.
Context Anchor
Seen in the coded leg types behind instrument approaches, departures, and missed approach procedures, especially when a procedure tells the aircraft to fly a heading to join another path.
Derivation
In ARINC 424 path-terminator coding, the first letter describes the path flown and the second letter describes how the leg ends. 'V' stands for a heading (Vector) flown through the air, and 'I' stands for Intercept. Knowing this two-letter system makes every leg type (CF, VA, VI, CI, etc.) easier to read at a glance.
Why Pilots Care
Connects a heading segment to a course or radial without needing a fixed waypoint.
Grounding Statement
Picture being told, “Fly this direction until you meet that road, then turn onto it.”
Intuition Check
Do not read “intercept” as a point you fly directly to. On a VI leg, the heading comes first; the leg ends only when the aircraft meets the next required path.
Example Sentence 1
After takeoff, the departure procedure included a VI leg directing the crew to fly heading 090 until intercepting the outbound course from the VOR.
Example Sentence 2
After takeoff the VI leg transitions the aircraft from runway heading onto the first enroute segment.