Abstract: A technique for assessing runway visibility to airborne infrared vision devices (EVS) determines the range performance of airborne infrared EVS sensors at a given destination and in real time by extending the modern RVR philosophy to the infrared spectrum. The technique measures extinction coefficients at the infrared sensor wavelengths of interest through deployment of ground-based infrared transmissometer systems. These infrared extinction coefficients are used with computational algorithms that are analogous to those used at visible wavelengths to determine the respective distances at which the background scene and runway lights are discernible using infrared cameras with appropriate image processing. In this technique, infrared sensors replace the human eye as a basic mechanism of sensing through the atmospheric path. The algorithms also account for the image processing and cockpit display functions, in accordance with the ultimate discernment by the pilot's eye when viewing an appropriate display device.