A specified surface sloping up and out from the edge of an approach surface and from a line originating at the end of the inner edge of each approach area, drawn parallel to the runway centerline in the direction of landing. The transitional surface identifies the height limitations on an object before it becomes an obstruction to air navigation. It extends outward and upward at right angles to the runway centerline, and the runway centerline is extended at a slope of 7-to-1 from the side of the primary surface and from the side of the approach surfaces. See takeoff climb surface.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved