In a three-RVR system, which statement is true?

• A. All three sensors must be operative
• B. Any one sensor suffices
• C. All three sensors are controlling, but at least two must be operative
• D. Only two sensors matter

Answer: (C)

In a three-RVR setup, visibility is measured at three points along the runway and all three readings feed the display. That means every sensor contributes to the reported RVR, so the sensors are described as controlling the readout. The system is designed with redundancy, so it can still provide a valid RVR as long as at least two sensors are operative. If only one sensor works, there isn’t enough data to support a reliable reading. So the correct idea is that all three sensors are part of the controlling system, but you need at least two to be functional to maintain operation.