The wind triangle graphically represents the relationships among velocity vectors used for air navigation.

The wind triangle is a graphical representation of the relationship between aircraft motion and wind. It is used extensively in dead reckoning navigation. Airbus A380 An aircraft is any machine capable of atmospheric flight. ... Wind is the roughly horizontal movement of air (as opposed to an air current) caused by uneven heating of the Earths surface. ... Dead reckoning is the process of estimating a global position of a vehicle by advancing a known position using course, speed, time and distance to be traveled. ... Table of geography, hydrography, and navigation, from the 1728 Cyclopaedia. ...

The wind triangle is a vector diagram, with three vectors. In physics and in vector calculus, a spatial vector is a concept characterized by a magnitude, which is a scalar, and a direction (which can be defined in a 3-dimensional space by the Euler angles). ...

• The air vector represents the motion of the aircraft through the airmass. It is described by true airspeed and true heading.
• The wind vector represents the motion of the airmass over the ground. It is described by wind speed and the inverse of wind direction. Note that by convention wind direction is given as the direction the wind is from. In a vector diagram such as the wind triangle, wind direction must be stated as the direction the wind is blowing to, or 180 degrees different from the convention.
• The ground vector represents the motion of the aircraft over the ground. It is described by ground track and ground speed. The ground vector is the resultant of algebraically adding the air vector and the wind vector.

The wind triangle describes the relationships among the quantities used in air navigation. When two of the three vectors, or four of the six components, are known, the remaining quantities can be derived. The three principle types of problems to solve are: True airspeed (TAS) is the speed of an aircraft relative to the airmass in which it flies, i. ... A heading is used to provide hierarchical information about other information. ... Wind speed is the speed of movement of air relative to a fixed point on the earth. ... Ground speed is the speed of an aircraft compared to the ground without factoring in the wind or other weather conditions. ... The principles of air navigation are the same for all aircraft, big or small. ...

1. Solve for the ground vector. This type of problem arises when true heading and true airspeed are known by reading the flight instruments and when wind direction and speed are known from either the meteorological forecast or from determination in flight.
2. Solve for the wind vector. This type of problem arises when determination of heading and true airspeed can be done by reading the flight instruments and ground track and ground speed can be found either by measuring the direction and distance between two established points of the aircraft or by determining the drift angle and groundspeed by reference to the ground.
3. Solve for true heading and groundspeed. This type of problem arises during flight planning or during a flight, when there is a need to determine a true heading to fly and a ground speed with which to compute an estimated time of arrival.

The traditional method of solving wind triangle equations is graphical. The known vectors are drawn to scale and in the proper direction on an aeronautical chart, using protractor and dividers. The unknown quantities are read from the chart using the same tools. Alternatively, the E6B flight computer (a circular slide rule with a translucent "wind face" on which to plot the vectors) can be used to graphically solve the wind triangle equations. A Tarom Boeing 737-300 and a United Airlines Boeing 777-200 taxi side by side at London Heathrow Airport. ... The estimated time of arrival or ETA is a measure of when a vehicle or aircraft in travel, cargo, or emergency services is expected to arrive at a certain place. ... The term protractor is used both in technics and surgery. ... The front of a metal E6B. An E6B flight computer commonly used by student pilots. ...

On aircraft equipped with advanced navigation equipment, the wind triangle is often solved within the flight management system, using inputs from the air data computer, inertial navigation system, global positioning system, and other instruments. The pilot simply reads the solution provided to him. A Flight Managment System is a little computer onboard almost every aircraft that will guide the aircraft to it designated destination. ... An air data computer is an essential avionics component found in modern glass cockpits. ... An inertial navigation system measures the position and altitude of a vehicle by measuring the accelerations and rotations applied to the systems inertial frame. ... GPS satellite in orbit, image courtesy NASA GPS redirects here. ...

References

• (1 December 1989) Air Navigation. Department of the Air Force. AFM 51-40.

see also

Set and drift are used to describe the current vector in marine navigation, analagous to wind in air navigation. In navigation set and drift are characteristics of the current in which a ship is sailing. ...