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Article 3: Zoning Districts
Section 3.8. Overlay Districts
3.8.2. Airport Overlay (AO) Districts
June 2013
Morrisville, NC
Page 3-70
Unified Development Ordinance - Public Hearing Draft
C.
Modifications of Otherwise Applicable Standards
1.
Uses Prohibited in Airport Overlay-A (AO-A) District
143
Irrespective of the use standards applicable in the underlying base, conditional, or planned
development district, or in any other applicable overlay district, certain uses shall be prohibited
in the Airport Overlay-A (AO-A) District, as indicated in the use tables in Article 4: Use
Standards.
2.
Underground Storage of Hazardous Chemicals and Substances
In the Airport Overlay-A District or Airport Overlay-B District, permanent or long-term storage of
significant qualities of highly explosive, flammable, toxic, corrosive, or otherwise hazardous
liquids, gases, chemicals, or other hazardous substances shall be located underground to reduce
the hazardous consequences from an airplane crash.
3.
Structure Height
144
The height of any structure in the Airport Overlay-A District or Airport Overlay-B District shall not
exceed that which constitutes an obstruction to air navigation, navigational aids, or navigational
facilities under standards of the Federal Aviation Administration (FAA) in 14 CFR Part 77,
Subpart C, as applied to the area around Raleigh-Durham International Airport, unless the FAA
determines no substantial obstruction exists in accordance with 14 CFR Part 77, Subpart D.
Documentation of compliance with this requirement may be required for any structure or structural
alteration that extends more than 50 feet above ground level.
4.
Outdoor Lighting
145
a.
Outdoor lighting in the Airport Overlay-A District or Airport Overlay-B District shall be
shielded to minimize direct skyward glare from the light source and otherwise located and
designed to avoid producing light emissions—whether direct or indirect (reflective) of such
intensity and directed in such directions as to impair pilot visibility or otherwise interfere with
the safe operation of overhead aircraft.
b.
Lighting of towers, tall buildings, and other potential obstructions to air navigation shall
include warning lighting that complies with FAA standards in Advisory Circular 70/7460-1
(Obstruction Marking and Lighting).
5.
Electronic Interference
146
No use, development, or activity in the Airport Overlay-A District or Airport Overlay-B District
shall produce electronic emissions that interfere with navigation signals or radio communications
between aircraft and landing control facilities or with aircraft navigational or communication
equipment.
143
Part B, Article III, Section 1.2.A (Subdistrict A, Prohibited Uses) of the current Zoning Ordinance lists a number of uses prohibited
in Subdistrict A. Those uses, modified to correspond to the uses as listed in the use tables and to add municipal solid waste landfills
(which attract substantial numbers of birds, posing a threat of interference with overhead aircraft) are shown as prohibited in
Article 4’s use tables.
144
Part C, Article III, Section 1.7 (Documentation) of the current Zoning Ordinance prohibits any building permit for a structure
whose height exceeds applicable restrictions of RDU and the FAA. RDU has no height restrictions applicable outside the airport
property and in the Town’s jurisdiction and the FAA does not actually apply any height restrictions. It only establishes notice
requirements, complex standards for determining what constitutes an obstruction to air navigation or navigational aids or facilities,
and a procedure whereby a person may use studies to show no substantial obstruction exists despite the standards. This subsection
modifies the current wording to specifically prohibit structure heights that would qualify as an obstruction under FAA determination
rules.
145
This modifies the provisions in Part C, Article III, Section 1.3 (Lighting) to more specifically prohibit lighting that would constitute
hazard to air navigation and specifically require compliance with FAA obstruction lighting guidelines.
146
This is a new provision generally prohibiting electronic interface with safe navigation.