Wind Triangle: Navigation Fundamentals

The Vector Geometry of Flight

The wind triangle is a graphical representation of the relationship between aircraft motion and wind. It consists of three vectors (lines that have both direction and magnitude):

• Air Vector: The aircraft movement through the air mass. The direction is True Heading, and the magnitude is True Airspeed (TAS).
• Wind Vector: The movement of the air mass itself over the ground. The direction is wind direction, and the magnitude is wind speed.
• Ground Vector: The aircraft actual path over the ground. The direction is True Course (Track), and the magnitude is Ground Speed (GS).

Solving the Triangle

In flight planning, you typically know your desired Ground Vector direction (your course to destination), your Air Vector magnitude (your airplane TAS), and the Wind Vector (from the weather forecast). The goal is to solve the triangle to find the missing variables: the Air Vector direction (the heading you need to steer) and the Ground Vector magnitude (how fast you will travel over the ground).

From E6B to Digital Calculators

For decades, pilots used the wind side of the E6B flight computer to physically draw the wind vector and slide the card to find the intersection of TAS and Course, revealing the required heading and ground speed.

Digital wind triangle calculators use the Law of Sines and Cosines to solve these vectors instantly, eliminating drawing errors and providing extreme precision. Understanding the underlying geometry, however, ensures you can spot-check the digital results for reasonableness.