THE VISIBILITY OF AIRPORT RUNWAYS ¹

The distance at which many airport runways can be seen under adverse weather conditions can be increased materially through the use of construction materials which will provide appropriate brightness contrast between the runways and their backgrounds. Since visual contact is essential to landing, and airports have prescribed minimums for visibility range, any method for increasing runway visibility will extend the weather conditions under which operations can continue. This will contribute to aviation safety, and will effect substantial cost savings for the airlines.

The brightness contrast between runway and terrain surfaces was measured at thirty eastern airfields. Large differences were found among these airfields. Some have runways constructed of materials having essentially the same reflectivity as the surrounding terrain. Others are constructed so as to maximize reflectivity differences and the resulting contrast. Various materials which are used for runway construction were measured photometrically and an average reflectivity value was calculated for each. Tables were prepared which show, in terms of present visibility theory, the effective runway visibility range that will result from the Use of different materials. This report provides a basis for the selection among a number of available materials those which will maximize the brightness contrast between runways and terrain and make the runway maximally visible.