Sec. 3-20. - Same — Further definitions and establishment of zones.

In order to carry out the purposes of this article, all of the land surfaces and air space within the boundaries of the county airport and all of the air space above the imaginary surfaces created and defined by this article are divided into clear zones, instrument runway approach zones, noninstrument runway approach zones, turning zones and transition zones as specifically outlined upon the map entitled "Airport Approach Zoning Map, Sonoma County Airport, Sonoma County, California," which is attached to the original ordinance from which this article derives and which is incorporated herein by reference and which map is hereby adopted as part of this article, and all of such zones are hereby created and established; provided, however, that reference to the land and air space below the imaginary surfaces defined by this article shall be made for the purposes of horizontal measurement of zone areas and for control of the height of trees or structures on such land which could, if not regulated, become hazards to aerial navigation.

(a)

Clear zones. The sloping trapezoidal imaginary surface and all the air space above such surface immediately adjacent to the ends of the landing areas which have been cleared of all above ground obstructions above the sloping surface starting at the end of such areas. Clear zones are included as a smaller component part of the instrument runway approach zones as defined in Section 3-19. The standard clear zone dimensions are two thousand five hundred feet (2,500′) in length (measured along the horizontally extended center line of the runway) and one thousand feet (1,000′) wide at the end closest to the runway, which width flares uniformly and symmetrically along the horizontally extended runway center line to the width of one thousand seven hundred and fifty feet (1,750′) at the end of the two thousand five hundred foot (2,500′) clear zone section. The imaginary surface slopes upward and outward from the ground elevation starting at the end of the landing and proceeds upward and outward at a ratio of one foot rise for each fifty feet (50′) of distance outward from the end of the landing area, measured along and parallel to the runway center line extended.

(b)

Instrument runway approach zones. The instrument runway approach zones consist of all the air space vertically above the instrument runway approach surfaces, and each is divided into a ten thousand foot (10,000′) section and an additional above the instrument runway approach surfaces, and each forty thousand foot (40,000′) section, these dimensions and slopes corresponding to those described in the definition in Section 3-19 of the instrument runway approach surfaces. The ten thousand foot (10,000′) section includes within the first two thousand five hundred feet (2,500′) a clear zone as described in subsection (a) of this section.

(c)

Noninstrument runway approach zones. The noninstrument runway approach zones consist of all the air space vertically above the noninstrument runway approach surfaces.

(d)

Transition zones. The transition zones consist of all the air space vertically above the transitional surfaces.

(e)

Turning zones. The turning zones consist of all the air space vertically above the horizontal surface and the conical surface.

(Ord. No. 629 § 5.)