Definition
A graphical method of flight planning in which three vectors — the wind, the aircraft's true heading and true airspeed, and the desired track and groundspeed — are drawn to scale to solve for unknown values such as wind correction angle, true heading, and groundspeed. Each vector represents both a direction and a magnitude, and when joined head-to-tail they form a triangle that shows how the wind moves the aircraft across the ground.
Plain English
A drawing that shows how wind pushes the airplane sideways during flight. By sketching three arrows — one for the wind, one for where the nose is pointed and how fast the airplane moves through the air, and one for the actual path over the ground — the pilot can work out how much to angle into the wind and how long the trip will really take.
Context Anchor
Seen in cross-country flight planning, navigation problems, and any situation where a pilot must account for wind before or during flight.
Derivation
A vector is a quantity with both direction and size, from the Latin 'vehere' meaning 'to carry.' The word fits because each arrow in the drawing carries the aircraft or the air a certain distance in a certain direction. 'Triangle' simply describes the shape formed when the three vectors are joined.
Why Pilots Care
Correct use prevents drifting off course, improves fuel planning, and ensures accurate time en route.
Analogy
Imagine rowing across a river. You have to point the boat slightly upstream to end up directly across, and the current changes how fast you actually cross. The wind triangle does the same job for an airplane in moving air.
Intuition Check
Do not read “triangle” as just a geometry shape. Here, the important idea is the relationship between three motions: the airplane through the air, the wind, and the airplane’s actual path over the ground.
Example Sentence 1
Before the cross-country flight, she used a wind triangle to find the heading that would keep her on course in a strong westerly wind.
Example Sentence 2
Vector analysis showed the groundspeed would be 15 knots slower than true airspeed due to the headwind component.