# Title 6 — Aeronautics Commission

## Article 6-02 — Aeronautics Commission

## Chapter 6-02-03.1 — Airport Runway Approach Hazards

### § 6-02-03.1-01. Definitions.

1. "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, and for which no precision approach facilities are planned, or
indicated on a planning document.
2. "Precision instrument runway" means a runway having an existing instrument approach
procedure utilizing an instrument landing system, or a precision approach radar. It also means
a runway for which a precision approach system is planned and is so indicated by an
approved airport layout plan or planning document.
3. "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.
4. "Visual runway" means a runway intended solely for the operation of aircraft using visual
approach procedures, with no straight-in instrument approach procedure and no instrument
designation indicated on an approved airport layout plan, or by any planning document
submitted to the North Dakota aeronautics commission by a competent authority.
History: Effective April 1, 2016.
General Authority: NDCC 2-05-07
Law Implemented: NDCC 2-03-12
### § 6-02-03.1-02. General.

Obstructions to air navigation are prohibited. The following rules, criteria, regulations, and minimum
standards governing the construction or maintenance of hazards or obstructions near runway
approaches to any airport that is open for public use in North Dakota, whether publicly or privately
owned, is hereby adopted by the North Dakota aeronautics commission pursuant to authority set forth
in North Dakota Century Code section 2-03-12.
History: Effective April 1, 2016.
General Authority: NDCC 2-03-12, 2-05-07, 2-05-21
Law Implemented: NDCC 2-03-12
### § 6-02-03.1-03. Procedure for determining obstructions.

This part establishes standards for determining obstructions to air navigation. It applies to existing
and proposed manmade objects, objects of natural growth, and terrain. The standards apply to the use
of navigable airspace by aircraft and to existing public airports. Additionally, the standards apply to a
planned public airport, or a change in an existing public airport, if a proposal therefore is on file with the
North Dakota aeronautics commission.

1. An existing object, including a mobile object, is, and a future object would be, an obstruction to
air navigation if it is of greater height than any of the following heights or surfaces:
a. A height of four hundred ninety-nine feet above ground level at the site of the object.
b. A height that is two hundred feet above ground level or above the established airport
elevation, whichever is higher, within three nautical miles of the established reference
point of an airport, excluding heliports, with its longest runway more than three thousand
two hundred feet in actual length, and that height increases in the proportion of one
hundred feet for each additional nautical mile of distance from the airport up to a
maximum of four hundred ninety-nine feet.
c. A height within a terminal obstacle clearance area, including an initial approach segment,
a departure area, and a circling approach area, which would result in the vertical distance
between any point on the object and an established minimum instrument flight altitude
within that area or segment to be less than the required obstacle clearance.
d. A height within an en route obstacle clearance area, including turn and termination areas,
of a federal airway or approved off-airway route, that would increase the minimum
obstacle clearance altitude.
e. The surface of a takeoff and landing area of an airport or any airport imaginary surface.
However, no part of the takeoff or landing area itself will be considered an obstruction.
2. Except for traverse ways on or near an airport with an operative ground traffic control service,
furnished by an air traffic control tower or by the airport management and coordinated with the
air traffic control service, the standards of subsection 1 of this section apply to traverse ways
used or to be used for the passage of mobile objects only after the heights of these traverse
ways are increased by:
a. Seventeen feet for an interstate highway that is part of the national system of military and
interstate highways where overcrossings are designed for a minimum of seventeen feet
vertical distance.
b. Fifteen feet for any other public roadway.
c. Ten feet or the height of the highest mobile object that would normally traverse the road,
whichever is greater, for a private road.
d. Twenty-three feet for a railroad.
e. For a waterway or any other traverse way not previously mentioned, an amount equal to
the height of the highest mobile object that would normally traverse it.
Failure to comply with the above regulations regarding obstructions to air navigation is prohibited under
this chapter.
History: April 1, 2016.
General Authority: NDCC 2-03-12
Law Implemented: NDCC 2-03-12
### § 6-02-03.1-04. Airport referenced imaginary surfaces.

The following airport imaginary surfaces are established with relation to the airport and to each
runway. The size of each imaginary surface is based on the classification of each runway and the type
of approach available or planned for that runway. Refer to Exhibit A for a table showing the

classification and dimensional standards. Refer to Exhibit B and C for a graphical depiction of the
imaginary surfaces.
1. Primary surface. 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; but when the runway has no specially prepared hard surface, or planned
hard surface, the primary surface ends at each end of that runway. The elevation of any point
on the primary surface is the same as the elevation of the nearest point on the runway
centerline. The width of a primary surface is:
a. Two hundred fifty feet for utility runways having only visual approaches.
b. Five hundred feet for utility runways having nonprecision instrument approaches.
c. For other than utility runways the width is:
(1) Five hundred feet for visual runways having only visual approaches.
(2) Five hundred feet for nonprecision instrument runways having visibility minimums
greater than three-fourths statute mile.
(3) One thousand feet for a nonprecision instrument runway having a nonprecision
instrument approach with visibility minimums as low as three-fourths of a statute
mile, and for precision instrument runways.
The width of the primary surface of a runway will be that width prescribed in this section for the most
precise approach existing or planned for either end of that runway.
2. Approach surface. A surface longitudinally centered on the extended runway centerline and
extending outward and upward from each end of the primary surface. An approach surface is
applied to each end of each runway based upon the type of approach available or planned for
that runway end.
a. The inner edge of the approach surface is the same width as the primary surface and it
expands uniformly to a width of:
(1) One thousand two hundred fifty feet for that end of a utility runway with only visual
approaches;
(2) One thousand fifty feet for that end of a runway other than a utility runway with only
visual approaches;
(3) Two thousand feet for that end of a utility runway with a nonprecision instrument
approach;
(4) Three thousand five hundred feet for that end of a nonprecision instrument runway
other than utility, having visibility minimums greater than three-fourths of a statute
mile;
(5) Four thousand feet for that end of a nonprecision instrument runway, other than
utility, having a nonprecision instrument approach with visibility minimums as low as
three-fourths statute mile; and
(6) Sixteen thousand feet for precision instrument runways.
b. The approach surface extends for a horizontal distance of:
(1) Five thousand feet at a slope of twenty to one for all utility and visual runways;

(2) Ten thousand feet at a slope of thirty-four to one for all nonprecision instrument
runways other than utility; and
(3) Ten thousand feet at a slope of fifty to one with an additional forty thousand feet at a
slope of forty to one for all precision instrument runways.
3. Horizontal surface. A horizontal plane one hundred fifty feet above the established airport
elevation, the perimeter of which is constructed by swinging arcs of specified radii from the
center of each end of the primary surface of each runway of each airport and connecting the
adjacent arcs by lines tangent to those arcs. The radius of each arc is:
a. Five thousand feet for all runways designated as utility or visual;
b. Ten thousand feet for all other runways. The radius of the arc specified for each end of a
runway will have the same arithmetical value. That value will be the highest determined
for either end of the runway. When a five thousand-foot arc is encompassed by tangents
connecting two adjacent ten thousand-foot arcs, the five thousand-foot arc shall be
disregarded on the construction of the perimeter of the horizontal surface.
4. Conical surface. 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.
5. Transitional surface. These surfaces extend outward and upward at right angles to the
runway centerline and the runway centerline extended at a slope of seven to one from the
sides of the primary surface and from the sides of the approach surfaces. Transitional
surfaces for those portions of the precision approach surface which project through and
beyond the limits of the conical surface, extend a distance of five thousand feet measured
horizontally from the edge of the approach surface and at right angles to the runway
centerline.
History: April 1, 2016.
General Authority: NDCC 2-03-12
Law Implemented: NDCC 2-03-12
### § 6-02-03.1-05. Penalty.

In accordance with North Dakota Century Code section 2-03-13, failure to comply with this section
constitutes a class A misdemeanor.
History: Effective April 1, 2016.
General Authority: NDCC 2-03-12
Law Implemented: NDCC 2-03-12

Dimensional Standards (Feet)
Visual Runway Nonprecision Instrument Runway Precision
Instrument
Runway
DIM Item A B A C D PIR
Width of primary
surface and approach
surface width at inner
A end 250 500 500 500 1,000 1,000
Radius of horizontal
B surface 5,000 5,000 5,000 10,000 10,000 10,000
Visual Approach Nonprecision Instrument Approach
Precision
Instrument
A B A C D Approach
Approach surface width
C at end 1,250 1,500 2,000 3,500 4,000 16,000
Approach surface
D length 5,000 5,000 5,000 10,000 10,000 *
E Approach slope 20:1 20:1 20:1 34:1 34:1 *
A - Utility runways
B - Runways larger than utility
C - Visibility minimums greater than three-fourths mile
D - Visibility minimums as low as three-fourths mile
* - Precision instrument approach is 50:1 for inner ten thousand feet and 40:1 for an additional forty
thousand feet


