17.44.020    Definitions.
   As used in the ordinance codified in this chapter,  unless the context otherwise requires:
   "Airport" means Chinook,  Harlem,  Turner and Hogeland Airport.
   "Airport elevation." Chinook—two thousand five hundred seventy six feet, Harlem—two thousand six hundred forty feet,  Turner—three thousand forty nine feet, Hogeland—3,138 feet,  above mean sea level, which is the highest point of an airport's useable landing area measured in feet from sea level.
   "Approach surface" means a surface longitudinally centered on the extended runway centerline,  extending outward and upward from the end of the primary surface and at the same slope as the approach zone height limitation slope set forth in Section 17.44.040.  In plan the perimeter of the approach surface coincides with the perimeter of the approach zone.
   "Approach, transitional, horizontal, and conical zones." These zones are set forth in Section 17.44.030.
   "Board of adjustment." A board consisting of five members appointed by the Blaine County commissioners as provided for in Sections 67-4-312,  67-6-206 and 76-2-321 through 76-2-328 Montana Codes Annotated.
   "Conical surface" means a surface extending outward and upward from the periphery of the horizontal surface at a slope of twenty to one for a horizontal distance of four thousand feet.
   "Hazard to air navigation" means an obstruction determined to have a substantial adverse effect on the safe and efficient utilization of the navigable airspace.
   "Height." For the purpose of determining the height limits in all zones set forth in the ordinance codified in this chapter and shown on the zoning map, the datum shall be mean sea level elevation unless otherwise specified.
   "Horizontal surface" means a horizontal plane one hundred fifty feet above the established airport elevation,  the perimeter of which in plan coincides with the perimeter of the horizontal zone.
   "Larger than utility runway" means a runway that is constructed for and intended to be used by propeller driven aircraft of greater than twelve thousand,  five hundred pounds maximum gross weight and jet powered aircraft.
   "Nonconforming use" means any preexisting structure, object of natural growth,  or use of land,  which is inconsistent with the provisions of the ordinance codified in this chapter or an amendment thereto.
   "Nonprecision instrument runway" means a runway having an existing instrument approach procedure utilizing air navigation facilities with only horizontal guidance, or area type navigation equipment,  for which a straight-in nonprecision instrument approach procedure has been approved or planned.
   "Obstruction" means any structure,  growth,  or other object,  including a mobile object, which exceeds a limiting height set forth in Section 17.44.040.
   "Person" means an individual,  firm, partnership, corporation,  company, association,  joint stock association or governmental entity; includes a trustee,  a receiver, an assignee,  or a similar representative of any of them.
   "Primary surface" means a surface longitudinally centered on a runway. When the runway has a specially prepared hard surface, the primary surface extends two hundred feet beyond each end of that runway; when the runway has no specially prepared hard surface,  or planned hard surface, the primary surface ends at each end of that runway. The width of the primary surface is set forth in Section 17.44.030. The elevation of any point on the primary surface is the same as the elevation of the nearest point on the runway centerline.
   "Runway" means a defined area on an airport prepared for landing and takeoff of aircraft along its length.
   "Structure" means an object,  including a mobile object, constructed or installed by man,  including but without limitation, buildings, towers, cranes, smokestacks, earth formation, and overhead transmission lines.
   "Transitional surfaces." These surfaces extend outward at ninety degree angles to the runway centerline and the runway centerline extended at a slope of seven feet horizontally for each foot vertically from the sides of the primary and approach surfaces to where they intersect the horizontal and conical surfaces.
   "Tree" means any object of natural growth.
   "Utility runway" means a runway that is constructed for and intended to be used by propeller driven aircraft of twelve thousand,  five hundred pounds maximum gross weight and less.
   "Visual runway" means a runway intended solely for the operation of aircraft using visual approach procedures.
(Ord.  495 § 2, 2003).