18 / 20
How is the meteorological visibility determined in the METAR?
  • A
    It is the greatest value which is reached at least within half of the horizon as seen from the aerodrome.
  • B
    The maximum determined by a meteorologist in a 360° scan at the horizon.
  • C
    The lowest observed in a 360° scan from the meteorological station.
  • D

    Given by transmissometer when the visibility is below 1500 metres.

ICAO Annex 3

Appendix 3
4.2 Visibility
4.2.4 Reporting
4.2.4.4 Recommendation.- In METAR and SPECI, visibility should be reporrted as prevailing visibility, as defined in Chapter 1. (...)

Chapter 1
Prevailing visibility. The greatest visibility value, observed in accordance with the definition of "visibility", which is reached within at least half the horizon circle or within at least half of the surface of the aerodrome. These areas could comprise contiguous or non-contiguous sectors.

Note: This value may be assessed by human observation and/or instrumented systems. When instruments are installed, they are used to obtain the best estimate of the prevailing visibility.

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.

  • Hungary
    3
  • Norway
    3
  • Austro Control
    2
  • Greece
    1
  • Poland
    1
  • Spain
    1
  • Sweden
    1
  • United Kingdom
    1
Keyboard Shortcut Use Keyboard Shortcuts