Intersection (aviation)
Encyclopedia
In aviation
, an intersection is a virtual
navigation
al fix
that helps aircraft
to maintain their flight plan
. It is usually defined as the intersection
(in the geometrical
sense) of two VOR
radial
s. They are usually identified as major airway intersections where aircraft, operating under instrument flight rules
, often change direction of flight
while en route. According to the Federal Aviation Regulations
, Part 91 Sec. 183, some intersections are designated as mandatory reporting points for pilots who are not in radar contact with air traffic control
.
Intersections also play an important role in departure and approach procedures. All intersections have an alphabet
ical or alphanumeric
designation. Near major airport
s, the intersection designation code typically consists of three letters followed by the runway
number. Most other intersection designations consist of five-letter combinations that are either pronounceable or chosen for their mnemonic
value, since either air traffic control
or the flight plan may require the pilot
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 Carrollton County Airport, there is a popular diner located on the field to which many pilots fly.
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
, an intersection is a virtual
Virtual
The term virtual is a concept applied in many fields with somewhat differing connotations, and also, differing denotations.The term has been defined in philosophy as "that which is not real" but may display the salient qualities of the real....
navigation
Navigation
Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...
al fix
Fix (position)
In position fixing navigation, a position fix or simply a fix is a position derived from measuring external reference points.The term is generally used with manual or visual techniques such as the use of intersecting visual or radio position lines rather than the use of more automated and accurate...
that helps aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
to maintain their flight plan
Flight plan
Flight plans are documents filed by pilots or a Flight Dispatcher with the local Civil Aviation Authority prior to departure...
. It is usually defined as the intersection
Line-line intersection
In Euclidean geometry, the intersection of a line and a line can be the empty set,a point, ora line. Distinguishing these cases, and finding the intersection point have use, for example, in computer graphics, motion planning, and collision detection....
(in the geometrical
Geometry
Geometry arose as the field of knowledge dealing with spatial relationships. Geometry was one of the two fields of pre-modern mathematics, the other being the study of numbers ....
sense) of two VOR
VHF omnidirectional range
VOR, short for VHF omnidirectional radio range, is a type of radio navigation system for aircraft. A VOR ground station broadcasts a VHF radio composite signal including the station's identifier, voice , and navigation signal. The identifier is typically a two- or three-letter string in Morse code...
radial
Radial
Radial can refer to:* Vector , a line* Radius, adjective form of* A radial pattern is one that appears to radiate from a point, like the spokes from the hub of a wheel* A bearing from a waypoint, such as a VOR...
s. They are usually identified as major airway intersections where aircraft, operating under instrument flight rules
Instrument flight rules
Instrument flight rules are one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other are visual flight rules ....
, often change direction of flight
Flight
Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....
while en route. According to the Federal Aviation Regulations
Federal Aviation Regulations
The Federal Aviation Regulations, or FARs, are rules prescribed by the Federal Aviation Administration governing all aviation activities in the United States. The FARs are part of Title 14 of the Code of Federal Regulations...
, Part 91 Sec. 183, some intersections are designated as mandatory reporting points for pilots who are not in radar contact with air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
.
Intersections also play an important role in departure and approach procedures. All intersections have an alphabet
Alphabet
An alphabet is a standard set of letters—basic written symbols or graphemes—each of which represents a phoneme in a spoken language, either as it exists now or as it was in the past. There are other systems, such as logographies, in which each character represents a word, morpheme, or semantic...
ical or alphanumeric
Alphanumeric
Alphanumeric is a combination of alphabetic and numeric characters, and is used to describe the collection of Latin letters and Arabic digits or a text constructed from this collection. There are either 36 or 62 alphanumeric characters. The alphanumeric character set consists of the numbers 0 to...
designation. Near major airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
s, the intersection designation code typically consists of three letters followed by the runway
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
number. Most other intersection designations consist of five-letter combinations that are either pronounceable or chosen for their mnemonic
Mnemonic
A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...
value, since either air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
or the flight plan may require the pilot
Aviator
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...
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 Carrollton County Airport, there is a popular diner located on the field to which many pilots fly.