local, state, and federal aviation regulations and policies, but sometimes must supersede
these due to national security interests. The Federal Aviation Administration (FAA) was
created as a result of the Act and serves a variety of purposes, including the management
of airspace over the US. The prime objectives of the FAA are to promote air safety and
the efficient use of the navigable airspace.
Another important outcome of the Act is Title 14 Code of Federal Regulation Part 77,
commonly referenced as simply Part 77, which provides the basis for evaluating if a
proposed structure or object will result in a vertical obstruction or flight hazard to
navigable airspace. Using a distance formula from this regulation, local jurisdictions can
assess the height restrictions near airfields. Additional information on Part 77 can be
found on the FAA website at http://www.faa.gov/. The FAA uses its Obstruction
Evaluation / Airport Airspace Analysis tool to generate Determinations of Hazards / No
Hazards for proposed structures or objects.
Part 77 establishes standards to determine obstructions within navigable airspace,
typically within a certain distance from an airport or airfield. The law defines an
obstruction to air navigation as an object that meets one or more of the following
conditions.
A height of 499 feet AGL at the site of the object.
A height that is 200 feet AGL or above the established airport elevation, whichever
is higher, and within three nautical miles of the established reference point of an
airport that has a runway of at least 3,200 feet in actual length. This excludes
heliports. This height criterium increases in the proportion of 100 feet for every
additional nautical mile from the airport, up to a maximum of 499 feet.
A height within a terminal obstacle clearance area, including an initial approach
segment, a departure area, or 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
clearance.
A height within an en route obstacle clearance area of a federal airway or
approved off‐airway route, including turn and termination areas, that would
increase the minimum obstacle clearance altitude.
The surface of a takeoff and landing area of an airport or of any imaginary surface,
as established under 77.19, DoD: 77.21, as well as heliports (77.23). However, no
part of the takeoff or landing area itself will be considered an obstruction.
Background Report
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