<strong>Observing of RVR</strong>
<strong>a.</strong> RVR observations must be representative of the touch down zone and, as may be selected by the authority concerned, of the middle and far sections of the runway.
<strong>b.</strong> RVR observations should be made on all runways intended for use during periods of reduced visibility and in particular on:<ul>
– Precision approach runways;
– Runways used for take-off and having high intensity edge lighting and/or centre-line lighting.
<strong>c.</strong> RVR observations should be carried out at a lateral distance from the runway centre-line of not more than 120 metres. The site for observations to be representative of the touch down zone should be located about 300 metres along the runway from the threshold.
The sites for observations to be representative of the middle and far sections of the runway should be located at a distance of 1000 to 1500 metres along the runway from the threshold and at a distance of about 300 metres from the other end of the runway. The exact position of these sites and, if necessary, additional sites should be decided after considering aeronautical, meteorological and climatological factors such as long runways, swamps and other fogprone areas.
<strong>d.</strong> RVR observations should be made during periods when the horizontal visibility is less than 1500 metres.
<strong>e.</strong> ATS units and other users at an aerodrome should be kept informed without delay of changes in the serviceability status of the RVR observing system.
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/1-horizontal-visibility-aspects/" title="1. Horizontal Visibility Aspects">1. Horizontal visibility aspects</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/2-visual-range/" title="2. Visual Range">2. Visual range</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/3-observing-techniques-rvr/" title="3. Observing Techniques of RVR">3. Observing techniques of RVR</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/4-observing-rvr/" title="4. Observing of RVR">4. Observing of RVR</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/5-availability-rvr-observations-ats-units/" title="5. Availability of RVR observations at ATS units">5. Availability of RVR observations at ATS units</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/6-reporting-procedures-rvr-reports/" title="6. Reporting procedures of RVR reports">6. Reporting procedures of RVR reports</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/7-accuracy-rvr-reports/" title="7. Accuracy of RVR reports">7. Accuracy of RVR reports</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/8-slant-visual-range/" title="8. Slant visual range">8. Slant visual range</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/9-visual-segment/" title="9. The visual segment">9. The visual segment</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/10-variation-visual-segment/" title="10. Variation in visual segment">10. Variation in visual segment</a>
<a href="http://flightcrewguide.com/wiki/meteorology/visibility/11-flight-visibility-vision-high-altitudes/" title="11. Flight visibility and vision at high altitudes">11. Flight visibility and vision at high altitudes</a>