Definition
An ARINC 424 path terminator (coded VM) defining a flight leg that begins at the end of the previous leg and continues on a specified heading until the pilot manually terminates it, typically by selecting the next leg or being given a vector by ATC. The leg has no defined endpoint in the navigation database; termination is by pilot action rather than by distance, altitude, fix, or intercept.
Plain English
A leg in a published procedure that says 'fly this heading until somebody tells you to stop or you decide to move on.' There is no fixed end point built into it — the pilot ends the leg when ATC issues a clearance or the next instruction is needed.
Context Anchor
Seen in instrument procedure coding, especially where a procedure expects radar vectors or further instructions after a published heading.
Derivation
In ARINC 424 path terminator coding, the two-letter code identifies the path (first letter) and the terminator (second letter). 'V' indicates a heading-based path; 'M' indicates manual termination. So 'VM' literally means heading path, manually ended.
Why Pilots Care
Ensures the aircraft follows ATC vectors without unintended turns until explicitly directed otherwise.
Analogy
It is like being told, “Drive straight ahead until I tell you where to turn,” instead of being told to drive to a specific intersection.
Intuition Check
Do not read “manual termination” as “the procedure is over.” It means this particular leg has no automatic ending point, so the pilot must continue the heading until the next instruction or action.
Example Sentence 1
After the missed approach climb, the procedure coded a VM leg on heading 310, so we held that heading until ATC issued vectors to rejoin the arrival.
Example Sentence 2
During the departure, the FMS flew the VM leg until the pilot selected direct to the next fix.