(A) Except as otherwise provided in this subchapter no structure or growth shall be erected, altered, allowed to grow, or maintained in any zone created by this subchapter to a height in excess of the height limit herein established for the zone. The reference plane for determination and establishment of height limits for the horizontal and conical surfaces shall be the elevation of the datum plane as follows:
Seven hundred sixty-three feet above mean sea level; the reference elevation for determination and establishment of the height limits for the approach and transition surfaces shall be the elevation (mean sea level) of the near end of the respective runway or landing strip, as the case may be.
(B) The height limit for each type zone is hereby established as follows:
(1) Approach surface zones (noninstrument runways). One foot of height for every 40 feet in horizontal distance, measured outward from the inner boundary of the respective approach surfaces;
(2) Approach surface (instrument landing system runways). One foot vertical to 50 feet horizontal, or at an angle of 01°08'45" from the horizontal for the first 10,000 feet, and thence continuing upward and outward at a slope ratio of one foot vertical to 40 feet horizontal, or at an angle of 1°23'56" from the horizontal for the next 40,000 feet;
(3) Horizontal surface zones. One hundred fifty feet above the established airport elevation;
(4) Conical surface zones. One foot of height for every 20 feet in horizontal distance, measured outward from the inner boundary of the respective conical surfaces; and
(5) Transition surface zones. One foot of height for every seven feet of horizontal distance, measured outward from the inner boundary of the respective conical surfaces.
(C) In addition to the requirements of divisions (A) and (B) of this section, structures or growths shall be considered obstructions to air navigation (unless special aeronautical study indicates otherwise) if they are more than 500 feet aboveground or fall in the following categories:
(1) Objects in instrument approach areas, more than 100 feet above the ground or 100 feet above the elevation of the approach end of the runway, whichever gives the higher elevation of the object, within three statute miles of the runway end, and increasing in height above ground in the proportion of 25 feet for each additional statute mile of distance outward from the runway end, but not to exceed 250 feet within ten statute miles of the runway end; or
(2) Objects more than 170 feet above the ground or more than 170 feet above the established airport elevation, whichever gives the higher elevation of the object, within three statute miles of the airport reference point, and increasing in height in the proportion of 100 feet for each additional mile of distance from the airport, but not to exceed a maximum of 500 feet above ground.
(1990 Code, § 5-118) (Ord. 67-924, passed 9-18-1967)