Definition
On an RNAV (area navigation) route, the point on the route at which the aircraft is closest to a referenced VOR station. It is the point where a line drawn perpendicular from the VOR meets the aircraft's track, and is used to define waypoints by bearing and distance from that VOR.
Plain English
The spot along your route where you pass closest to a particular VOR ground station. It is the point where a straight line from the VOR meets your route at a right angle.
Context Anchor
Seen in aircraft drawings, maintenance layout work, and airport surface diagrams that show straight sections joining curves.
Derivation
From the Latin tangere, 'to touch.' A tangent is a line that just touches a curve or another line at one point. The tangent point is that single touching point — here, the spot where a line from the VOR just touches your route at a right angle.
Why Pilots Care
It identifies the maximum or minimum latitude on a route so fuel, performance, and airspace requirements can be calculated accurately.
Analogy
Think of a ruler touching the outside edge of a coin at one tiny spot. That tiny spot is the tangent point.
Intuition Check
A tangent point is not just any point on a curve. It is the exact place where a line touches the curve smoothly without crossing through it.
Example Sentence 1
The waypoint was defined by its bearing and distance from the VOR measured at the tangent point.
Example Sentence 2
Flight planning software marks the tangent point so the crew can confirm the highest latitude and associated fuel burn.