[Code of Federal Regulations]

[Title 14, Volume 2]

[Revised as of January 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 14CFR77.23]



[Page 186-187]

 

                     TITLE 14--AERONAUTICS AND SPACE

 

CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION 

                               (CONTINUED)

 

PART 77_OBJECTS AFFECTING NAVIGABLE AIRSPACE--Table of Contents

 

                     Subpart C_Obstruction Standards

 

Sec. 77.23  Standards for determining obstructions.



    (a) 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:

    (1) A height of 500 feet above ground level at the site of the 

object.

    (2) A height that is 200 feet above ground level or above the 

established airport elevation, whichever is higher, within 3 nautical 

miles of the established reference point of an airport, excluding 

heliports, with its longest runway more than 3,200 feet in actual 

length, and that height increases in the proportion of 100 feet for each 

additional nautical mile of distance from the airport up to a maximum of 

500 feet.

    (3) 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



[[Page 187]]



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.

    (4) 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.

    (5) The surface of a takeoff and landing area of an airport or any 

imaginary surface established under Sec. 77.25, Sec. 77.28, or Sec. 

77.29. However, no part of the take-off or landing area itself will be 

considered an obstruction.

    (b) 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 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) 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 17 feet vertical distance.

    (2) Fifteen feet for any other public roadway.

    (3) Ten feet or the height of the highest mobile object that would 

normally traverse the road, whichever is greater, for a private road.

    (4) Twenty-three feet for a railroad, and,

    (5) 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.



[Doc. No. 10183, 36 FR 5970, Apr. 1, 1971]