14.08.070 AC Airport compatibility district.

A. Boundaries. The boundaries of an airport district shall be determined by application of the following zones or sub-districts around the Walterboro Municipal Airport or any proposed airport.

1. Approach Zones.

a. Approach zones include all land, which lies directly under an imaginary approach surface longitudinally centered on the extended centerline at each end of a runway. The inner edge of an approach surface is at the same width and elevation as, and coincides with, the end of the primary surface, unless otherwise specified.

b. The dimensions of an approach zone shall be determined on the basis of the following:

i. Runway protected zone shall include the area identified on a map of the Walterboro-Colleton County Airport, Land Use Plan, by Pearson Engineering, 1998, which map shall be made a part of this section.

ii. Visual approach utility runway shall expand outward from the primary surface uniformly to a width of one thousand two hundred fifty (1,250) feet at a horizontal distance of five thousand (5,000) feet from the primary surface.

iii. Nonprecision instrument utility runway shall have an established width of five hundred (500) feet at the inner edge of the primary surface, and shall expand outward uniformly to a width of two thousand (2,000) feet at a horizontal distance five thousand (5,000) feet from the primary surface.

iv. Runway instrument utility visual approach runway shall extend outward from the primary surface uniformly to a width of one thousand five hundred (1,500) feet at a horizontal distance of five thousand (5,000) feet from the primary surface.

v. Runway larger than a utility runway with a visibility minimum greater than three quarters of one mile nonprecision instrument approach shall expand outward from the primary surface uniformly to a width of three thousand five hundred (3,500) feet at a horizontal distance of ten thousand (10,000) feet from the primary surface.

vi. Runway larger than a utility runway with a visibility minimum as low as three quarters of one mile nonprecision instrument, approach shall have an established width of one thousand (1,000) feet, and shall expand outward from the primary surface uniformly to a width of four thousand (4,000) feet at a horizontal distance of ten thousand (10,000) feet from the primary surface.

vii. Precision instrument runway shall have an established width of one thousand (1,000) feet and shall expand outward from the primary surface uniformly to a width of sixteen thousand (16,000) feet at a horizontal distance of fifty thousand (50,000) feet from the primary surface.

2. Transitional Zones. Transitional zones are the areas beneath the transitional surfaces. The dimensions of a transitional zone shall determined on the basis of the following:

a. Transitional Zone Determination for Airports. Refer to subsection 14.08.070(C), “Height Restrictions for Transitional Uses.”

b. Transitional Zone Determination for Heliports. These zones extend outward from the sides of the primary surface a horizontal distance of two hundred fifty (250) feet from the primary surface centerline.

3. Horizontal Zones. The horizontal zone is established by swinging arcs of five thousand (5,000) feet radii for utility visual runways and ten thousand (10,000) feet radii for all other runways, from the center of each end of the primary surface of each runway and connecting the adjacent arcs by drawing lined tangent to those arcs. The horizontal zone does not include the approach or the transitional zones.

4. Conical Zones. The conical zone is established as the area that commences at the periphery of the horizontal zone and extends outward therefrom a horizontal distance of four thousand (4,000) feet.

B. Permitted-Prohibited Uses. The AC district is an “overlay” zone. As such, permitted uses are determined by the “underlying” or primary district. However, these regulations are intended to temper and modify the use and development standards of the primary district to the extent necessary to achieve the stated purpose of this district, Section 14.04.020. To that end, primary district regulations are hereby amended to prohibit the following:

1. In All Airport Zones. Any use which would:

a. Create electrical interference with navigational signals or radio communication between the airport and aircraft;

b. Diminish the ability of pilots to distinguish between airport lights and other lights;

c. Result in glare in the eyes of pilots using the airport;

d. Impair visibility in the vicinity of the airport;

e. Create bird strike hazards, or otherwise in any way endanger or interfere with the landing, takeoff, or maneuvering of aircraft intending to use the airport.

2. In the Ultimate Runway Protected Zone (Shown on the previously referenced Walterboro-Colleton County Airport, Land Use Plan Map).

a. Single-family residential dwellings, including mobile or manufactured dwellings in excess of two units per acre;

b. Multi-family dwellings, cluster housing projects, mobile or manufactured home parks, and group housing;

c. Transient lodging, motels and hotels;

d. Hospitals, sanatoriums, and nursing homes;

e. Schools and day care centers; and

f. Churches, theaters, auditoriums, and similar places of assembly.

C. Height Restrictions. Except as otherwise provided in this title, no structure shall be erected, altered, or maintained, and no tree shall be allowed to grow in any zone within the airport compatibility district to a height in excess of the applicable height limits herein established for such zone, as follows:

1. Approach Zones. Height limitations for approach zones shall be determined for the various runways by calculating a slope ratio (measured in feet outward and upward) from the end of and at the same elevation as the primary surface extending along the runway centerline to a prescribed horizontal distance, as follows: 2. Airport Transitional Zone. Height limits for an airport transitional zone shall be determined by measuring outward and upward at a 7:1 slope from the sides of and at the same elevation as the approach surface, and extending to the point of intersection with a horizontal surface or conical surface.

3. Horizontal Zone. Height limits in the horizontal zone are established at one hundred fifty (150) feet above airport elevation.

4. Conical Zone. Height limits in the conical zone are established by measuring from the periphery of the horizontal zone and at one hundred fifty (150) feet above elevation outward and upward at 20:1 slope to a height of three hundred fifty (350) feet above airport elevation.

	Horizontal Distance	Slope Ratio
Utility visual runway	5,000'	20:1
Utility nonprecision instrument approach runway	5,000'	20:1
Runway larger than utility with visual approach	5,000'	20:l
Runway larger than utility with visual minimum greater than 3/4 mile, nonprecision instrument approach	10,000'	34:1
Runway larger than utility with visual minimum as low as 3/4 mile, nonprescription instrument approach	10,000'	34:1
Precision instrument approach runway	10,000'	50:1
Plus additional	40,000'	40:1

D. Noise Restrictions. Noise restrictions shall apply within the approach zone of a precision instrument runway only. Private airports and all runways designed for other than precision instrument landings shall be exempt from the provisions of this section.

Where permitted within the approach zone of an airport district, residential dwellings and portions of buildings where public will be received, shall be structurally designed and constructed to achieve an outdoor to indoor peak noise level reduction (NLR) of at least thirty decibels (30 db). All other permitted uses and structures shall be exempt from this section.

Normal construction can be expected to provide an NLR of twenty decibels (20 db), thus the actual required reduction is only ten decibels (10 db). Lowering the NLR shall be achieved through incorporation into the design and construction of all proposed uses, sound insulation materials and methods for improving acoustic insulation performance.

A description, of such methods and materials shall accompany all building applications for uses affected by this section, and shall be subject to approval by the director of planning and facilities.

E. Lighting Regulations. No permitted use, subdivision, or project in an airport district shall have outdoor lighting or illumination arranged and/or operated in such a manner as to be misleading or pose a danger to aircraft operations.

F. Regulations Applicable to Existing Structures. The owner of any existing structure or vegetation that is currently penetrating any referenced surface within an established airport district shall permit the installation, operation, and maintenance thereon of whatever markers and lights deemed necessary by the Federal Aviation Administration, or the South Carolina Aeronautics Commission to indicate to the operators of aircraft in the vicinity of an airport the presence of an airport obstruction. These markers and lights shall be installed, operated, and maintained at the expense of the airport operator.

However, the regulations prescribed in this section shall not be construed to require the removal, lowering, or other change or alteration of any existing structure or tree not conforming to the regulations as of December 5, 2000, or otherwise interfere with the continuance of an existing use. Nothing contained herein shall require any change in the construction, alternation, or intended use of any structure, the construction or alternation of which was begun prior to December 5, 2000, and is diligently prosecuted.

G. Variances. Any person desiring to erect or increase the height or size of any structure not in accordance with the regulations prescribed in this section may apply for a variance from such regulations to the zoning board of appeals, in accord with the provisions of Chapter 14.36. The application for a variance shall be accompanied by a determination from the Federal Aviation Administration as to the effect of the proposal on the operation of air navigation facilities and the safe, efficient use of navigable airspace.

Additionally, no application for a variance to the requirements of this title may be considered by the board unless a copy of the application has been furnished to the airport operator for advice as to the aeronautical effects of the variance. If the airport operator does not respond to the application within fifteen (15) days after receipt, the board may act on its own to grant or deny the application for a variance.

Any permit or variance granted, if such action is deemed advisable to effectuate the purpose of this title and be reasonable in the circumstances, may be so conditioned as to require the owner of the structure in question to install, operate, and maintain at the owner’s expense, such markings and lights as may be deemed necessary by the Federal Aviation Administration, the South Carolina Aeronautics Commission, and the airport operator. (Ord. 99-O-25 § 2.7, 1999)