Sec. 3-19. - Same — Further definitions; airport referenced imaginary surfaces.

Imaginary surfaces are established by reference to the landing area and to the airport reference point and consist of instrument runway approach surfaces, noninstrument runway approach surfaces, a horizontal surface, a conical surface, and transitional surfaces defined as follows:

(a)

Instrument runway approach surfaces. The instrument runway approach surface is an inclined plane located directly above the land lying below the instrument runway approach zone as hereinafter defined and consists of an imaginary surface sloping upward and outward and from each end of the landing area and starting its slope at the elevation of the ground at the end of the landing area. This surface consists of two (2) sections measured horizontally out from a point beginning two hundred feet (200′) outward from the end of each runway. The inner section has a length of ten thousand feet (10,000′) and includes within the first two thousand five hundred feet (2,500′) a clear zone as defined in Section 3-20. The outer section of the surface extends outward and upward an additional forty thousand feet (40,000′) measured horizontally along the ground below the surface. The surface is symmetrically located with respect to the runway center line extended and has a total width of one thousand feet (1,000′) at the end closest to the runway. The surface flares uniformly to a total width of four thousand feet (4,000′) at the end of the ten thousand foot (10,000′) section and to a total width of sixteen thousand feet (16,000′) at the end of the forty thousand foot (40,000′) section. The slope of the surface shall be fifty (50) to one for the inner ten thousand foot (10,000′) section and forty (40) to one for the outer forty thousand foot (40,000′) section. The surface requirements specified in this article for instrument runways shall apply to all runways which may be used for instrument operation and to both ends of such runways.

(b)

Noninstrument runway approach surfaces. A noninstrument runway approach surface is an inclined plane consisting of an imaginary sloping surface starting at the ground elevation at each end of the landing area of a noninstrument runway and sloping upward and outward from the horizontally extended runway center line. These surfaces have a total length of ten thousand feet measured horizontally from a point beginning two hundred feet (200′) outward from each end of a noninstrument runway. These approach surfaces each have a total width of five hundred feet (500′) at the end closest to the end of the runway which width flares uniformly along the horizontally extended center line of the runway to a total width of two thousand five hundred feet (2,500′) at the end of the ten thousand foot (10,000′) section. For all runways not intended for instrument operation, this approach surface slope shall be forty (40) to one.

(c)

Horizontal surface. The horizontal surface is a level plane circular in shape with its height one hundred and fifty feet (150′) above the published airport elevation of one hundred and twenty-five feet (125′) mean sea level as established by the United States civil aeronautics authority (now the United States federal aviation agency) and has a radius from the airport reference point of ten thousand feet (10,000′).

(d)

The conical surface. The conical surface extends upward and outward from the periphery of the horizontal surface with a slope of twenty (20) to one measured by reference to vertical planes radiating outward in all directions from the airport reference point. Thus measured radially outward from the periphery of the horizontal

surface, the conical surface extends from such periphery for a horizontal distance of five thousand feet.

(e)

Transitional surface. The transitional surfaces are inclined planes with a slope of seven (7) to one measured upward and outward in a vertical plane at right angles to the center line of the runway. The transitional surfaces, symmetrically located on either side of the runway, extended upward and outward from a line on either side of the runway which is parallel to and level with the runway center line. These parallel lines are at a horizontal distance from the runway center line equal to ½ of one thousand feet (1,000′) (five hundred feet (500′)) or ½ of five hundred feet (500′) (two hundred and fifty feet (250′)) as indicated in subsection (a) or (b) above, as the case may be. Transitional surfaces also extend from the edges of all of the approach surfaces upward and outward to the intersection with the horizontal surface, or the conical surface. The approach surfaces for instrument runways projecting through and beyond the limits of the conical surface have a seven (7) to one transitional surface extending a distance of five thousand feet (5,000′) measured horizontally from the edge of the approach surfaces and at right angles to the runway center line.

(Ord. No. 629 § 4.)