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– within 5,000 feet of a public use heliport which exceeds a 25:1 surface .
Any highway , railroad , or other traverse way whose prescribed adjusted height would exceed the above noted standards .
When requested by the FAA :
– Any construction or alteration located on a public use airport or heliport regardless of height or location .
Part 77 also identifies the height at which an object may be considered an obstruction at a designated distance :
§ 77.17‐ Obstruction standards .
( 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 499 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 three 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 from the airport up to a maximum of 499 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 between any point on the object and an established minimum instrument flight altitude with segment to be less than the required ob
( 4 ) A height within an en route obstacle including turn and termination areas , of approved off‐airway route , that would in minimum obstacle clearance altitude .
( 5 ) The surface of a takeoff and landing any imaginary surface established unde 77.23 . However , no part of the takeoff o will be considered an obstruction .
( b ) Except for traverse ways on or near a operative ground traffic control service f airport traffic control tower or by the air and coordinated with the air traffic cont standards of paragraph ( a ) of this sectio ways used or to be used for the passage only after the heights of these traverse w by :
( 1 ) 17 feet for an Interstate Highway tha National System of Military and Intersta overcrossings are designed for a minimu distance .
( 2 ) 15 feet for any other public roadway
( 3 ) 10 feet or the height of the highest m would normally traverse the road , which private road .
( 4 ) 23 feet for a railroad .
( 5 ) For a waterway or any other traverse mentioned , an amount equal to the heig mobile object that would normally trave