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Old October 2nd 06, 11:40 PM posted to rec.aviation.soaring
Mike the Strike
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Posts: 952
Default another question for you USA FAR experts: tetrahedrons

"The landing direction indicator--A tetrahedron is installed when
conditions at the airport warrant its use. It may be used to indicate
the direction of landings and takeoffs. A Tetrahedron may be located at
the center of a segmented circle and may be lighted for night
operations. The small end of the tetrahedron points in the direction of
landing. Pilots are cautioned against using the tetrahedron for any
purpose other than as an indicator of landing direction. Further,
pilots should use extreme caution when making runway selection by use
of a tetrahedron in very light or calm wind conditions as the
tetrahedron may not be aligned with the designated calm-wind runway."

Says it all. That's why I call for surface winds before I land.

Mike

Vaughn Simon wrote:
wrote in message
ps.com...
Is the tetrahedron at an airport:

1) Supposed to be pinned down to show active runway
2) Allowed to be pinned down to show active runway
3) Supposed to pivot freely with the wind direction

(Background: our club has a long-standing policy to anchor the
tetrahedron. Some of us are really scratching our heads about this
policy and would like to change it. We already know that "the
tetrahedron is not a wind indicator".)


I don't know what (if anything) the FARs say about that, but it is covered
in the AIM (Section 4-3-4) "Pilots are cautioned against using a tetrahedron
for any purpose rather than as an indicator of landing direction." Curiously,
the section seems to be silent on your specific question, but does say that a
wind tee can be manually pointed as long as it is co-located with a wind
indicator.

Thanks for an interesting topic. I learned something.

Vaughn