Tetrahedron

A tetrahedron is a large landing direction indicator — a three-sided pyramid (tetrahedron shape) mounted on a pivot, free to rotate in the wind. The small end of the tetrahedron points into the wind, indicating the preferred landing direction. It is used at uncontrolled aerodromes to show pilots the active runway direction.

Using the Tetrahedron

The small end (apex) of the tetrahedron points into wind — the direction aircraft should land. Land in the same direction the apex is pointing, toward the tetrahedron. The tetrahedron is a passive wind vane; always cross-check with the windsock and other traffic to confirm the active direction before committing to a landing.

Related Terms

See also: Active Runway, ATF.