In
aviation
Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' include fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air aircraft such as h ...
, an intersection is a virtual navigational
fix that helps
aircraft
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...
maintain their
flight plan
Flight plans are documents filed by a aviator, pilot or flight dispatcher with the local Air Navigation Service Provider (e.g., the Federal Aviation Administration, FAA in the United States) prior to departure which indicate the plane's planned ...
. It is usually defined as the
intersection
In mathematics, the intersection of two or more objects is another object consisting of everything that is contained in all of the objects simultaneously. For example, in Euclidean geometry, when two lines in a plane are not parallel, their ...
(in the
geometrical sense) of two
VOR (VHF Omnidirectional Range)
radials. They are usually identified as major airway intersections where aircraft, operating under
instrument flight rules
In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR).
The U.S. Federal Aviation Administration's (FAA) ''Instrument Fl ...
, often change direction of
flight
Flight or flying is the motion (physics), motion of an Physical object, object through an atmosphere, or through the vacuum of Outer space, space, without contacting any planetary surface. This can be achieved by generating aerodynamic lift ass ...
while ''en route''. According to the
Federal Aviation Regulations
The Federal Aviation Regulations (FARs) are rules prescribed by the Federal Aviation Administration (FAA) governing all aviation activities in the United States. The FARs comprise Title 14 of the Code of Federal Regulations (14 CFR). A wide var ...
, some intersections are designated as mandatory reporting points for pilots who are not in radar contact with
air traffic control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...
.
Intersections also play an important role in departure and approach procedures. All intersections have an
alphabet
An alphabet is a standard set of letter (alphabet), letters written to represent particular sounds in a spoken language. Specifically, letters largely correspond to phonemes as the smallest sound segments that can distinguish one word from a ...
ical or
alphanumeric
Alphanumericals or alphanumeric characters are any collection of number characters and letters in a certain language. Sometimes such characters may be mistaken one for the other.
Merriam-Webster suggests that the term "alphanumeric" may often ...
designation. Near major
airport
An airport is an aerodrome with extended facilities, mostly for commercial Aviation, air transport. They usually consist of a landing area, which comprises an aerially accessible open space including at least one operationally active surf ...
s, the intersection designation code typically consists of three letters followed by the
runway
In aviation, a runway is an elongated, rectangular surface designed for the landing and takeoff of an aircraft. Runways may be a human-made surface (often asphalt concrete, asphalt, concrete, or a mixture of both) or a natural surface (sod, ...
number. Most other intersection designations consist of five-letter combinations that are either pronounceable or chosen for their
mnemonic
A mnemonic device ( ), memory trick or memory device is any learning technique that aids information retention or retrieval in the human memory, often by associating the information with something that is easier to remember.
It makes use of e ...
value, since either
air traffic control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled air ...
or the flight plan may require the
pilot
An aircraft pilot or aviator is a person who controls the flight of an aircraft by operating its Aircraft flight control system, directional flight controls. Some other aircrew, aircrew members, such as navigators or flight engineers, are al ...
to announce the designation. In the terminal procedure or approach plate example to the right, note that two of the intersections are called DONUT and KOFFE. Many intersections are named because of local points of interest. In the case of Carroll County Airport, there is a popular diner located on the field to which many pilots fly.
See also
*
Fix (position)
Geopositioning is the process of determining or estimating the geographic position of an object or a person.
Geopositioning yields a set of geographic coordinates (such as latitude and longitude) in a given map datum. Geographic positions may a ...
*
Position line
A position line or line of position (LOP) is a line (or, on the surface of the Earth, a curve) that can be both identified on a chart (nautical chart or aeronautical chart) and translated to the surface of the Earth. The intersection of a minimum ...
*
Intercept method In astronomical navigation, the intercept method, also known as Marcq St. Hilaire method, is a method of calculating an observer's position on Earth (geopositioning). It was originally called the ''azimuth intercept'' method because the process inv ...
*
Intersection (land navigation) Position resection and intersection are methods for determining an unknown geographic position ( position finding) by measuring angles with respect to known positions.
In ''resection'', the one point with unknown coordinates is occupied and sightin ...
References
''Instrument Procedures Handbook'' Federal Aviation Administration, 2007. FAA-H-8261-1A. Retrieved 2010-12-04.
Air navigation
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