What is the purpose of forward scatter visibility sensors at an airport?

• A. To measure visibility along the runway for RVR or visibility reporting.
• B. To calibrate altimeters
• C. To detect bird strike risk
• D. To measure wind direction only

Answer: (A)

Forward scatter visibility sensors are used to quantify how far the eye can see by measuring light that is scattered forward by airborne particles. This gives a numerical value for prevailing visibility, which is the general visibility condition reported in weather observations like METAR and, when integrated with runway systems, helps support RVR or visibility reporting. In practice, this sensor provides an automatic, continuous readout of how far pilots can see in the field of view, which is essential for situational awareness and regulatory reporting.

This tool is not for calibrating altimeters, detecting wind direction, or assessing bird strike risk. Altimeter calibration relies on pressure data and standard procedures; wind direction is measured by wind sensors; bird strike risk involves different detection systems.