A wind sock indicates wind direction and speed as the wind blows through the
larger opening through to its smaller end. If the wind sock is hanging
limp, calm wind is indicated. The more straight out the wind sock is
extended, the higher the indicated wind speed. The size of wind socks and
the relative size of the large and small openings varies. This means one
wind sock might fly straight out with 15 knots of wind, while another might have
a bend half way up its length with 15 knots.
The large opening of the wind sock faces the direction from which the wind
At some airports, a landing tee is installed, which indicates wind direction but
not speed. The wind tee swings with the wind so that it is readable as the
letter "T" when you are facing into the wind.
At some airports, the landing tee might be manually set by persons at the
airport. As a result, a landing tee may not always accurately reflect wind
A tetrahedron is a wind direction indicator that points the direction from which
the wind is blowing. Tetrahedrons provide no indication of wind speed.
At some airports, the tetrahedron might be set manually. Be cautioned that
the tetrahedron might not accurately reflect wind direction.
Some airports utilize a segmented circle, which provides wind and traffic
pattern procedures information to pilots. The segmented circle consists of
a landing direction indicator or wind direction indicator, such as a tetrahedron
or wind sock, surrounded by traffic pattern indicators.
These traffic pattern indicators visually depict the base and final legs of the
traffic pattern, as they align with the appropriate runway when viewed from above.
As a pilot flies over this segmented circle, it can be seen that the traffic
pattern for the north-south runway is meant to remain on the west side of the
airport. The traffic patterns for the east-west runway are to remain north
of the airport.