Runway Visibility Value (RVV) is the visibility determined for a runway by which instrument?

• A. Transmissometer
• B. Radar
• C. Barometer
• D. Anemometer

Answer: (A)

The Runway Visibility Value is determined by a transmissometer. This instrument sends a beam of light along a fixed path the length of the runway; the atmosphere attenuates that light as fog, haze, or other aerosols affect visibility. The receiver measures how much light makes it through and converts that into a distance—how far you can see along the runway. That measured distance is the RVV (often called RVR in practice), which pilots use to judge landing and takeoff conditions.

Radar, barometer, and anemometer measure something different—radar detects targets or precipitation with radio waves, a barometer measures air pressure, and an anemometer measures wind speed—so they don’t provide the fixed-path runway visibility value.