698 

14 CFR Ch. I (1–1–19 Edition) 

§ 77.19 

flight altitude within that area or seg-
ment to be less than the required ob-
stacle clearance. 

(4) A height within an en route obsta-

cle clearance area, including turn and 
termination areas, of a Federal Airway 
or approved off-airway route, that 
would increase the minimum obstacle 
clearance altitude. 

(5) The surface of a takeoff and land-

ing area of an airport or any imaginary 
surface established under § 77.19, 77.21, 
or 77.23. However, no part of the take-
off or landing area itself will be consid-
ered an obstruction. 

(b) Except for traverse ways on or 

near an airport with an operative 
ground traffic control service furnished 
by an airport traffic control tower or 
by the airport management and coordi-
nated with the air traffic control serv-
ice, the standards of paragraph (a) 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: 

(1) 17 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 17 feet vertical distance. 

(2) 15 feet for any other public road-

way. 

(3) 10 feet or the height of the highest 

mobile object that would normally tra-
verse the road, whichever is greater, 
for a private road. 

(4) 23 feet for a railroad. 
(5) For a waterway or any other tra-

verse way not previously mentioned, 
an amount equal to the height of the 
highest mobile object that would nor-
mally traverse it. 

§ 77.19

Civil airport imaginary sur-

faces. 

The following civil airport imaginary 

surfaces are established with relation 
to the airport and to each runway. The 
size of each such imaginary surface is 
based on the category of each runway 
according to the type of approach 
available or planned for that runway. 
The slope and dimensions of the ap-
proach surface applied to each end of a 
runway are determined by the most 
precise approach procedure existing or 
planned for that runway end. 

(a) 

Horizontal surface. 

A horizontal 

plane 150 feet above the established air-
port elevation, the perimeter of which 
is constructed by SW.inging arcs of a 
specified radii from the center of each 
end of the primary surface of each run-
way of each airport and connecting the 
adjacent arcs by lines tangent to those 
arcs. The radius of each arc is: 

(1) 5,000 feet for all runways des-

ignated as utility or visual; 

(2) 10,000 feet for all other runways. 

The radius of the arc specified for each 
end of a runway will have the same ar-
ithmetical value. That value will be 
the highest determined for either end 
of the runway. When a 5,000-foot arc is 
encompassed by tangents connecting 
two adjacent 10,000-foot arcs, the 5,000- 
foot arc shall be disregarded on the 
construction of the perimeter of the 
horizontal surface. 

(b) 

Conical surface. 

A surface extend-

ing outward and upward from the pe-
riphery of the horizontal surface at a 
slope of 20 to 1 for a horizontal distance 
of 4,000 feet. 

(c) 

Primary surface. 

A surface longitu-

dinally centered on a runway. When 
the runway has a specially prepared 
hard surface, the primary surface ex-
tends 200 feet beyond each end of that 
runway; but when the runway has no 
specially prepared 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 the primary surface is: 

(1) 250 feet for utility runways having 

only visual approaches. 

(2) 500 feet for utility runways having 

non-precision instrument approaches. 

(3) For other than utility runways, 

the width is: 

(i) 500 feet for visual runways having 

only visual approaches. 

(ii) 500 feet for non-precision instru-

ment runways having visibility mini-
mums greater than three-fourths stat-
ute mile. 

(iii) 1,000 feet for a non-precision in-

strument runway having a non-preci-
sion instrument approach with visi-
bility minimums as low as three- 
fourths of a statute mile, and for preci-
sion instrument runways. 

VerDate Sep<11>2014 

16:30 Jun 25, 2019

Jkt 247047

PO 00000

Frm 00708

Fmt 8010

Sfmt 8010

Q:\14\14V2.TXT

PC31

kpayne on VMOFRWIN702 with $$_JOB