surveying iii (topographic and geodetic surveys) - Modern Prepper

An inner horizontal surface is an oval plane that is at a height 150 feet above theestablished airfield elevation. The plane is constructed by scribing an arc with a radius of7,500 feet at the centerline at the end of each runway. The arcs are then interconnectedwith tangents. A conical surface is a surface extending from the periphery of the inner horizontal surfaceoutward and upward at a slope of 20:1. The horizontal distance is 7,000 feet, with aheight of 500 feet above the established airfield elevation. An outer horizontal surface is a plane, 500 feet above the established airfield elevation,extending outward from the outer periphery of the conical surface for a horizontaldistance of 30,000 feet.(2) Related to Runways. A primary surface may be located on the ground or the water. The primary surface islongitudinally centered on each runway and is the same length as the runway. The widthof the primary surface for runways is 2,000 feet; however, at established bases wheresubstantial construction has taken place according to previous lateral-clearance criteria,the 2,000-foot width may be reduced to the former criteria. A clear-zone surface may be located on the ground or on water at each end of the primarysurface. The length is 1,000 feet, and the width is the same as the primary surface. An approach/departure-clearance surface is an inclined plane, symmetrical at theextended runway centerline, beginning 200 feet beyond each end of the primary surface atthe centerline elevation of the runway end and extending for 50,000 feet. The slope ofthe approach-clearance surface is 50:1 along the runway-centerline and extended until itreaches an elevation of 500 feet above the established airport elevation. It then continueshorizontally at this elevation to a point 50,000 feet from the point of beginning. Thewidth of this surface at the runway end is the same as the primary surface, then it flaresuniformly and the width at 50,000 feet is 16,000 feet. A transitional surface connects the primary surfaces, the first 200 feet of the clear-zonesurfaces, and the approach/departure-clearance surfaces to the inner horizontal surface,the conical surface, the outer horizontal surface, or other transitional surfaces. The slopeof the transitional surface is 7:1 outward and upward at right angles to the runwaycenterline.6-7 EN0593