Sec. 26-104. AP Airport Height Restrictive Overlay District.
   (a)   Purpose.  It is the intent of the AP Overlay District to restrain influences that are adverse to the property and safe conduct of aircraft operations in the vicinity of Jim Hamilton-L.B. Owens Airport and McEntire Air National Guard Base.  Furthermore, it is the intent of this overlay district to prevent creation of conditions hazardous to aircraft operation, to prevent conflict with land development that may result in loss of life and property, and to encourage development that is compatible with airport use characteristics.
   (b)   Applicability/Establishment.  The AP Overlay District shall function as an overlay district, providing additional requirements to the regulations of the underlying general use zoning classification(s).
   (c)   Permitted uses, permitted uses with special requirements, and special exceptions.  The AP Overlay District may contain several different underlying general use zoning classifications. All uses permitted in the respective underlying zoning districts shall be permitted in the AP Overlay District.  Provided, however, when the provisions of this section impose higher standards than are required for that zoning classification, the provisions of this section shall apply. However, no use may be made of land or water within the AP Overlay District in such a manner as to cause or create electrical interference with navigational signals or radio communication between any airport and the aircraft, make it difficult for pilots to distinguish between airport lights and others, result in glare in the eyes of pilots using any airport, create bird strike hazards, or otherwise in any way endanger or interfere with the landing, take off, or maneuvering of aircraft using or intending to use any airport.
   (d)   Development standards.
      (1)   General.  Except as specifically provided for below, no material changes shall be made in the use of land, no structure shall be erected or otherwise established, and no tree shall be planted in any AP Overlay District unless a permit is applied for and granted. The following exceptions shall apply:
         a.   In the area lying within the limits of the AP horizontal zone (see subparagraph (2)e. below) and the AP conical zone (see subparagraph (2)f. below), no permit shall be required for any tree or structure less than seventy-five (75) feet in vertical height above the ground, except when, due to terrain, land contour, or topographic features, such tree or structure would extend above the height limits prescribed for such zones.
         b.   In areas lying within the limits of the AP approach zones (see subparagraph (2)b. below), but at a horizontal distance of not less than four thousand two hundred (4,200) feet from each end of the runway, no permit shall be required for any tree or structure less than seventy- five (75) feet in vertical height above the ground, except when, due to terrain, land contour, or topographic features, such tree or structure would extend above the height limits prescribed for such zones.
         c.   In the areas lying within the limits of the AP transition zones (see subparagraph (2)d. below), no permit shall be required for any tree or structure less than seventy-five (75) feet in vertical height above the ground, except when, due to terrain, land contour, or topographic features, such tree or structure would extend above the height limits prescribed for such zones.
      (2)   Height standards:  Except as otherwise provided in this section, no structure shall be erected, altered, or maintained, and no trees shall be allowed to grow in any zone created by this section to a height in excess of the applicable height limitations established in this section for each zone in question, as follows:
         a.   Primary zones:  APP.
            1.   McEntire Air National Guard Base (APPM):  The primary zone is established at field elevation, two hundred fifty-one (251) feet, mean sea level, longitudinally centered on each runway with the same length as the runway.  The width of the primary zone is two thousand (2,000) feet.
            2.   Jim Hamilton-L.B. Owens Airport (APPO):  None.
         b.   Approach zones:  APA.
            1.   McEntire Air National Guard Base (APAM):  The approach zone begins two hundred (200) feet beyond each end of the primary surface at the centerline elevation of the runway end and extends for fifty thousand (50,000) feet. The slope of the approach clearance zone is fifty (50) to one (1) along the runway centerline extended until it reaches an elevation of five hundred (500) feet above the established airport elevation (equal to 251 feet mean sea level). It then continues horizontally at this elevation to a point fifty thousand (50,000) feet from the point of beginning. The width of this surface at the runway end is the same as the primary surface, flaring uniformly, with width at the fifty thousand (50,000) feet point being sixteen thousand (16,000).
            2.   Jim Hamilton-L.B. Owens Airport (APAO):  The approach zone slopes twenty (20) feet outward for each one (1) foot upward beginning at the end of and at the same elevation as the primary surface and extending to a horizontal distance of five thousand (5,000) feet along the extended runway centerline.
         c.   Clear zones:  APCZ.
            1.   McEntire Air National Guard Base (APCZM):  The clear zone is established at field elevation (251 feet mean sea level) and extends outward from the primary surface to the length of one thousand (1,000) feet. The width is equal to the width of the primary surface.
            2.   Jim Hamilton-L.B. Owens Airport (APCZO):  None.
         d.   Transitional zones:  APT.
            1.   McEntire Air National Guard Base (APTM): The transitional zones connect the primary surface, the first two hundred (200) feet of the clear zone surface, and the approach clearance surface to the inner horizontal surfaces, conical surface, and outer horizontal surface.  The slopes of the transitional surface are seven (7) to one (1) outward and upward at right angles to the runway centerline beginning at the sides of and at the same elevation as the primary surface (251 feet mean sea level).
            2.   Jim Hamilton-L.B. Owens Airport (APTO): The transitional zone slopes seven (7) feet outward for each one (1) foot upward beginning at the side of and at the same elevation as the primary surface and the approach surface, and extend to a height of one hundred fifty (150) feet above the airport elevation (194 feet mean sea level). In addition to the foregoing, there are established height limits sloping seven (7) feet outward for each one (1) foot upward beginning at the sides and at the same elevation as the approach surface, and extending to where they intersect the horizontal surface.
         e.   Horizontal zones:  APH.
            1.    McEntire Air National Guard Base (APHM):  The horizontal zones for McEntire National Guard Base are separated into the inner horizontal zone and the outer horizontal zone.  Their dimensions are:
         Inner:  The inner horizontal zone is an oval shape at a height of one hundred fifty (150) feet above the established airfield (equal to 401 feet mean sea level).
         Outer:  The outer horizontal zone is a plane located five hundred (500) feet above the established airfield elevation (equal to 751 feet mean sea level), extending outward from the outer periphery of the conical surface for a horizontal distance of thirty thousand (30,000) feet.
            2.   Jim Hamilton-L.B. Owens Airport:  The horizontal zone is established at one hundred fifty (150) feet above the airport elevation (equal to 344 feet mean sea level).
         f.   Conical zones:  APC.
            1.   McEntire Air National Guard Base (APCM):  The conical zone is a surface extending from the periphery of the inner horizontal surface outward and upward at a slope of twenty (20) to one (1) for a horizontal distance of seven thousand (7,000) feet to a height of five hundred (500) feet above the established airfield elevation (equal to 751 feet mean sea level).
            2.   Jim Hamilton-L.B. Owens Airport:  The conical zone slopes twenty (20) feet outward for each one (1) foot upward beginning at the periphery of the horizontal zone and at one hundred fifty (150) feet above the airport elevation (equal to 344 feet mean sea level) and extending to an elevation of three hundred fifty (350) feet above the airport elevation (equal to 544 feet mean sea level) at a horizontal distance of four thousand (4,000) feet.
      (3)   Other dimensional and use regulations. Permitted accessory structures, prohibited uses and structures, minimum lot area, minimum lot width, minimum yard requirements, maximum lot coverage, minimum off-street parking and loading requirements, regulation of signs, and provisions of sidewalks and open space shall be provided as regulated in the general zoning district to which the AP Overlay District is appended, unless the AP Overlay District has a greater requirement upon such dimensions and characteristics of use, in which case the stricter shall prevail.
      (4)   Obstruction marking and lighting.  Any permit or variance granted may, if such action is deemed advisable to effectuate the purpose of this section and is reasonable in the circumstances, be so conditioned as to require the owner of the structure or tree in question to install, operate, and maintain, at the owner’s expense, such markings and lighting as may be necessary.  If deemed proper by the board of zoning of appeals and acceptable to the county, this condition may be modified to require the owner to permit the county, at the county’s expense, to install, operate, and maintain the necessary markings and lights.
   (e)   Variances.
      (1)   General.  Any person desiring to erect or increase the height of any structure, or permit the growth of any tree, or use the property not in accordance with the regulations provided in this section, may apply to the board of zoning appeals for a variance from such regulations.
      (2)   FAA review.  The application for a variance shall be accompanied by a determination of the Federal Aviation Administration (FAA) as to the effect of the proposal on the operation of air navigation facilities and the safe, efficient use of navigable airspace. Such variances shall be allowed when it is duly found that a literal application or enforcement of the regulations will result in unnecessary hardship, and relief, if granted, will not be contrary to the public interest, will not create a hazard to air navigation, will do substantial justice, and will be in accordance with the spirit of this chapter.
      (3)   Airport management review.  No application for a variance of these regulations may be considered by the board of zoning appeals unless notification of the request and a copy of the application have been furnished to the airport manager for advice as to the aeronautical effects of the variance. If the airport manager does not respond to the notification within fifteen (15) days after receipt, the board of zoning appeals may act on its own to grant or deny the application.
   (f)   Nonconforming uses.
      (1)   General.  The regulations prescribed by this section shall not be construed to require the removal, lowering, or other change or alteration of any structure or tree not conforming to the regulations as of the effective date of this chapter, or otherwise interfere with the continuance of a nonconforming use. However, the owner of any existing nonconforming structure or tree is hereby required to permit the installation, operation, and maintenance thereon of such markers or lighting as shall be deemed necessary by the county to indicate to the operators of aircraft in the vicinity of the airport the presence of such airport obstruction. Such markers shall be installed, operated, and maintained at the expense of the county.
      (2)   Abandoned or destroyed.
         a.   Structure. Whenever the zoning administrator determines that a nonconforming structure has been destroyed or torn down beyond seventy- five percent (75%) of its most recent appraised value, no permit shall be granted that would allow such structure to exceed the applicable height limit or otherwise deviate from the zoning regulations.
         b.   Tree. Whenever the zoning administrator determines that a nonconforming tree has been destroyed, torn down, decayed or deteriorated, below the applicable height limit, no permit shall be granted that would allow another tree to be planted which would exceed the applicable height limit or otherwise deviate from the regulations contained in this section.
(Ord. No. 074-04HR, § V, 11-9-04; Ord. No. 043-07HR, § XXI, 5-1-07; Ord. No. 029-09HR,  § II, 5-19-09; Ord. No. 054-09HR, § XXI, 11-3-09)