1. Primary Surface. A surface longitudinally centered on the runway and extending two hundred feet beyond each runway end. The primary surface is at the same elevation as the elevation of the nearest point on the runway centerline. The primary surface width is two hundred fifty feet.

2. Approach Surface. Inclined planes extending upward and outward from the ends of the primary surface. The approach surface is two hundred fifty feet wide at the intersection with the primary surface. It extends outward for a distance of five thousand feet at a twenty-to-one slope and is one thousand feet at its widest point.

3. Transitional Surface. A surface extending outward and upward, at right angles to the runway centerline and runway centerline extended, from the sides of the primary surface and the approach surfaces. The slope is seven to one and the surface extends until it intersects with the horizontal surface.

4. Horizontal Surface. Horizontal plane one hundred fifty feet above the established airport elevation, the perimeter of which is constructed by swinging arcs of specified radii from the center of each end of the primary surface of each runway. Tangents then connect the adjacent arcs. The radius of each arc is five thousand feet.

5. Conical Surface. A surface which extends upward and outward from the outer limits of the horizontal surface for a horizontal distance of four thousand feet. The slope of the conical surface is twenty to one measured in a vertical plane.