13.5.1 A wind direction indicator should be located
on the unit which, in so far as is practicable, indicates the wind
conditions over the TLOF in such a way as to be free from the effects
of airflow disturbances caused by nearby objects or rotor downwash.
It should be visible from a helicopter in flight or in a hover over
the helideck. Where the TLOF may be subject to a disturbed air flow
then additional wind direction indicators located close to the area
should be provided to indicate the surface wind on those areas. Placement
of the wind direction indicators should not compromise obstacle-protected
surfaces.
13.5.2 Units on which night helicopter operations
take place should have provisions to illuminate the wind direction
indicators.
13.5.3 A wind direction indicator should be a
truncated cone made of lightweight fabric and should have the following
minimum dimensions:
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|
Length
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1.2 m
|
|
|
Diameter (larger end)
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0.3 m
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|
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Diameter (smaller end)
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0.15 m
|
13.5.4 The colour of the wind direction indicator
should be so selected as to make it clearly visible and understandable
from a height of at least 200 m above the heliport, having regard
to background. Where practicable, a single colour, preferably white
or orange, should be used. Where a combination of two colours is required
to give adequate conspicuity against changing backgrounds, they should
preferably be orange and white, or red and white, and should be arranged
in five alternate bands the first and last band being the darker colour.