(A) Airspace zones. In order to carry out the purposes of this chapter, the following airspace zones are hereby established: primary zone, horizontal zone, conical zone, approach zone and transitional zone and whose locations and dimensions are as follows:
(1) Primary zone. All that land which lies directly under an imaginary primary surface longitudinally centered on a runway and extending 200 feet beyond each end of the runways. The elevation of any point on the primary surface is the same as the elevation of the nearest point on the runway centerline. The width of the primary surface is 500 feet for all runways.
(2) Horizontal zone. All that land which lies directly under an imaginary horizontal surface 100 feet above the established airport elevation, or a height of 1,226 feet above mean sea level, 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 and connecting the adjacent arcs by lines tangent to those arcs. The radius of each arc is 10,000 feet for all runways.
(3) Conical zone. All that land which lies directly under an imaginary conical surface extending upward and outward for the periphery of the horizontal surface at a slope of 20 to 1 for a horizontal distance of 4,000 feet.
(4) Approach zone. All that land which lies directly under an imaginary approach surface longitudinally centered on the extended centerline at each end of all runways. The inner edge of the approach surface is at the same width and elevation as, and coincides with, the primary surface. The approach surface inclines upward and outward at a slope of 40 to 1, expanding uniformly to a width of 3,500 feet at a horizontal distance of 10,000 feet, and then continuing at the same rate of divergence to the periphery of the conical surface.
(5) Transitional zone. All that land which lies directly under an imaginary transitional surface extending upward and outward at right angles to the runway centerline and the runway centerline extended at a slope of 7 to 1 from the sides of the primary surfaces and from the sides of the approach surfaces until they intersect the horizontal surface or the conical surface.
(B) Height restriction. Except as otherwise provided in this chapter, and except as necessary and incidental to airport operations, no structure or tree shall be constructed, altered or allowed to grow in any airspace zone created division (A) above so as to project above any of the imaginary airspace surfaces described in division (A) above. Where an area is covered by more than one height limitation, the more restrictive limitations shall prevail.
(`86 Code, § 12.04)