Simulation Study of Chevron Markings For Areas Adjacent To Runway Threshold

 To determine the minimum system of chevron markings that would give warning of potentially deceptive, nonload - bearing paved areas before runway threshold, 20 pilots were given systematic exposure in a flight simulator to narrowed and more widely spaced chevron patterns, and also to the present U.S. Standard.  The judgements made by these pilots were that both the conventional pattern of full-width chevrons spaced 100 feet apart and a pattern of standard-width chevrons spaced 200 feet apart provided distinct and unambiguous warning of the nonloadbearing surface.  Further, they reported that these two patterns were not confusable with other markings such as the runway threshold stripes.  Pilot judgments of the two patterns with narrowed chevrons were mixed.  While a majority reported the narrowed chevrons not confusable, there was a marked increase in the number reporting absence of distinct and unambiguous guidance, particularly when the markings were viewed from a position low on glide slope and offset from the centerline.