If the reported RVR differs from actual conditions by more than 400 feet, how should the RVR data be treated?

• A. Is acceptable
• B. Should be used
• C. Is not acceptable
• D. Is invalid

Answer: (C)

RVR readings must be trusted to support landing decisions. If the reported Runway Visual Range differs from the actual conditions by more than 400 feet, that reading is not acceptable for use. A discrepancy of this magnitude signals a reliability issue with the sensor or measurement, so pilots and controllers should not base decisions on it. Instead, rely on other visibility indicators such as prevailing visibility from METAR, observer reports, or nearby sensor data, and seek verification or recalibration of the RVR system before using it for operations. The important idea is that only RVR data within an acceptable accuracy range should influence decisions; when it exceeds that range, it should be disregarded.