How is RVR typically measured?

RVR, or Runway Visual Range, is measured primarily by transmissometers, which are optical devices that assess how much light is transmitted through the atmosphere along the runway. These devices typically utilize a laser or light source positioned at a specific height, often around 14 feet, which helps to minimize the impact of ground obstructions and vegetation on visibility readings. The transmissometer detects the amount of light that is scattered or absorbed by particles in the air, providing precise data on the visual range available to pilots during landing and takeoff.

This method of measurement is particularly effective in various weather conditions, such as fog or heavy precipitation, where visual observation might not provide an accurate assessment of visibility. The technology allows for real-time reporting, which is crucial for maintaining safety and efficient operations at airports.