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This article is about airport runways. For fashion model runways, see
[7]catwalk. For the ITV quiz programme "Runway", see [8]Runway (game
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Colombia.
Runway 13R/31L of [13]El Dorado International Airport, [14]Bogotá,
D.C., Colombia.
[15]Aerial picture of a runway of Chennai International Airport,
Chennai, India
Aerial picture of a runway of [16]Chennai International Airport,
[17]Chennai, [18]India
A runway (RWY) is a strip of land on an [19]airport, on which
[20]aircraft can [21]take off and [22]land. Runways may be a man-made
surface (often [23]asphalt, [24]concrete, or a mixture of both) or a
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* [31]4 "Sections" of a runway
* [32]5 Runway lighting
+ [33]5.1 History
+ [34]5.2 Technical specifications
* [35]6 Runway markings
+ [36]6.1 National variants
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* [39]8 Active runway
* [40]9 Longest runways
* [41]10 See also
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Runways are generally numbered according to their magnetic [45]heading
(the takeoff direction it is "pointing towards"). The runway number is
the whole number nearest one-tenth the magnetic [46]azimuth of the
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Each digit is pronounced separately for clarity in radio
communications. For example, Runway Three Six would be aligned in
roughly a 360 [47]degrees direction ([48]magnetic north), Runway Nine
would be used for a runway with a 94 degree-alignment (close to
magnetic east), and Runway One Seven for 168 degrees. Each runway can
be used in either direction, and hence has two numbers, each 180°
apart. Thus, Runway One Zero (100°) becomes Runway Two Eight (280°)
when used in the opposite direction and Runway One Eight (180°)
becomes Runway Three Six (360°). Runways in [49]North America that lie
within the [50]Northern Domestic Airspace are, because of the
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[54]United States military (such as [55]Edwards Air Force Base)
airports, numbers for runways less than 100° include the leading
"zero", for example, Runway Zero Two or Runway Zero One Left. However
in the [56]United States at most [57]civil aviation airports, numbers
for runways less than 100° are often given as single digits; for
instance, Runway Nine or Runway Four Right. This also includes some
military airfields such as [58]Cairns Army Airfield. This American
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country such as Canada for a controller to clear an incoming American
aircraft to, for example, Runway 04, and the pilot read back the
clearance as Runway 4. Users of flight simulation programs may note
that those of American origin might apply U.S. usage to airports
around the world. For example Runway 05 at Halifax (CYHZ) will appear
on the FS program as the single digit 5 rather than 05.
Runway designations do change over time. Because the magnetic poles
slowly drift on the Earth's surface, but the runways stay fixed, the
magnetic bearing will change. Depending on the airport location and
how much drift takes place, it may be necessary over time to change
the runway designation. As runways are designated with headings
rounded to the nearest 10 degrees, this will affect some runways more
than others. For example,if the magnetic heading of a runway is 276
degrees , it would be designated Runway 28. If the magnetic heading
changed upwards by 5 degrees, a huge change, the Runway would still be
Runway 28. If on the other hand the original magnetic heading was 284
(Runway 28), and the heading increased by only two degrees to 286, the
runway should become Runway 29. Because the drift itself is quite
slow, runway designation changes are relatively uncommon, and not
welcomed, as they do require an accompanying change in a wide range of
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If there is more than one runway pointing in the same direction
(parallel runways), each runway is identified by appending Left (L),
Center (C) and Right (R) to the number -- for example, Runways One
Five Left (15L), One Five Center (15C), and One Five Right (15R).
Runway Zero Two Left (02L) becomes Runway Two Zero Right (20R) when
used in the opposite direction (derived from adding 18 to the original
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At large airports with more than three parallel runways (for example,
at [59]Los Angeles International Airport in [60]Los Angeles,
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[62]Romulus, Michigan or [63]Hartsfield-Jackson International Airport
in [64]Atlanta, Georgia), some runway identifiers are shifted by 10
degrees to avoid the ambiguity that would result with more than three
parallel runways. In [65]Los Angeles, this system results in Runways
Six Left, Six Right, Seven Left, and Seven Right, even though all four
runways are exactly parallel (approximately 69 degrees).
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ground speed needed to attain flying speed. Larger airports usually
have several runways in different directions, so that one can be
selected that is most nearly aligned with the wind. Airports with one
runway are often constructed to be aligned with the [67]prevailing
wind.
Runway dimensions vary from as small as 800 ft (244 m) long and 25 ft
(8 m) wide in smaller [68]general aviation airports, to 18,000 ft
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Two runways pointing in the exact same direction are classed as dual
or parallel runways depending on the separation distance. In some
countries, flight rules mandate that only one runway may be used at a
time under certain conditions (usually adverse [74]weather) if the
parallel runways are too close to each other.
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TORA
[76]Takeoff Run Available - The length of runway declared
available and suitable for the ground run of an airplane taking
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LDA
[78]Landing Distance Available - The length of runway which is
declared available and suitable for the ground run of an
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* The Runway Strip is the cleared, grassy area around the paved
runway. It is kept free from any obstacles that might impede
flight or ground roll of aircraft, although the grass is not
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with white cones or gables.
* The Runway is the entire paved surface, which typically features
threshold markings, numbers, centerlines, and overrun areas at
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* Blast pads, also known as overrun areas or stopways, are often
constructed just before the start of a runway where [80]jet blast
produced by large planes during the takeoff roll could otherwise
erode the ground and eventually damage the runway. Overrun areas
are also constructed at the end of runways as emergency space to
slowly stop planes that overrun the runway on a landing gone
wrong, or to slowly stop a plane on an aborted take-off or a
take-off gone wrong. Blast pads are often not as strong as the
main paved surface of the runway and are marked with yellow
chevrons. Planes are not allowed to taxi, take-off or land on
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* The Displaced threshold is the point at the end of the runway. In
major airports, it is usually marked with white paint arrows that
lead up to the [81]displaced threshold (see diagram). Smaller
runways may not have markings to indicate the displaced threshold.
The threshold area may be used for taxiing and takeoff but not for
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[[82]edit] Runway lighting
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The first runway lighting appeared in 1930 at [84]Cleveland Municipal
Airport (now known as Cleveland Hopkins International Airport) in
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Runway lighting is used at airports which allow night landings. Seen
from the air, runway lights form an outline of the runway. A
particular runway may have some or all of the following.
* [87]Runway End Identification Lights (REIL) Unidirectional (facing
approach direction) or omnidirectional pair of synchronized
flashing lights installed at the runway threshold, one on each
side.
* Runway end lights A pair of four lights on each side of the runway
On precision instrument runways, these lights extend along the
full width of the runway. These lights show green when viewed by
approaching aircraft and red when seen from the runway.
* [88]Runway Edge Lights White elevated run the length of the runway
on either side. On precision instrument runways, the edge-lighting
becomes yellow in the last 2,000 ft (610 m) of the runway.
[89]Taxiways are differentiated by being bordered by blue lights,
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taxiway, and the complexity of the taxi pattern.
* Runway Centerline Lighting System (RCLS) Lights embedded into
surface of the runway at 50 ft (15 m) intervals along the runway
centerline on some precision instrument runways. White except last
3,000 ft (914 m), alternate white and red for next 2,000 ft
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over the first 3,000 ft (914 m) (or to the midpoint, whichever is
less) of the runway.
* Taxiway Centerline Lead-Off Lights Installed along lead-off
markings, alternate green and yellow lights embedded into runway
pavement. It starts with green light about runway centerline to
the position of first centerline light beyond holding position on
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* Land and Hold Short Lights A row of white pulsating lights
installed across the runway to indicate hold short position on
some runways which are facilitating [90]LAHSO operations.
* [91]Approach Lighting System or ALS, is a lighting system
installed on the approach end of an airport runway and consists of
a series of lightbars, strobe lights, or a combination of the two
that extends outward from the runway end.
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also avoids the cost of having the lighting system on for extended
periods. Smaller airports may not have lighted runways or runway
markings. Particularly at private airfields for light planes, there
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[[102]edit] Runway markings
There are various runway markings and signs on any given runway.
Larger runways have a distance remaining sign (black box with white
numbers). This sign uses a single number to indicate the thousands of
feet remaining, so 7 will indicate 7,000 ft (2,134 m) remaining. The
runway threshold is marked by a line of green lights.
There are three types of runways:
* Visual Runways are used at small airstrips and are usually just a
strip of grass, gravel, asphalt or concrete. Although there are
usually no markings on a visual runway they may have threshold
markings, designators, and centerlines. Additionally, they do not
provide an instrument-based landing procedure; pilots must be able
to see the runway to use it. Also, radio communication may not be
available and pilots must be self-reliant.
* Non-precision instrument runways are often used at small-medium
size airports. These runways, depending on the surface, may be
marked with threshold markings, designators, centerlines, and
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(VOR), [105]Global Positioning System, etc.
* Precision instrument runways, which are found at medium and large
size airports, consist of a blast pad/stopway (optional, for
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2,000 ft (610 m), 2,500 ft (762 m), and 3,000 ft (914 m) touchdown
zone marks. Precision runways provide both horizontal and vertical
guidance for instrument approaches.
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Kingdom, as well as some other countries all 3-stripe and 2-stripe
touchdown zones for precision runways are replaced with one-stripe
touchdown zones.
* In Australia, precision runways consist of only one 1-stripe
touchdown zone, aiming point, and one 1-stripe touchdown zone.
Furthermore, all non-precision and visual runways lack an aiming
point.
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3-stripe touchdown zone.
* Runways in [112]Norway have yellow markings instead of the usual
white ones. This also occurs on some airports in Japan. The yellow
markings are used to ensure better contrast against snow.
* Runways may have different types on each end. To cut costs, many
airports do not install precision guidance equipment on both ends.
Runways with one Precision end and any other type of end can
install the full set of touchdown zones, even if some are past the
midpoint. If a runway has Precision markings on both ends,
touchdown zones within 900 ft (274 m) of the midpoint are omitted,
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[114]Typical runway surface seen at Congonhas International Airport in
São Paulo, Brazil. The grooves seen here simultaneously increase
friction and reduce the risk of hydroplaning.
Typical runway surface seen at [115]Congonhas International Airport in
[116]São Paulo, [117]Brazil. The grooves seen here simultaneously
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The choice of material used to construct the runway depends on the use
and the local ground conditions. Generally speaking, for a major
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pavements, this is generally found to be unnecessary, with the
exception of [119]expansion joints across the runway where a
[120]dowel assembly, which permits relative movement of the concrete
slabs, is placed in the concrete. Where it can be anticipated that
major settlements of the runway will occur over the years because of
unstable ground conditions, it is preferable to install [121]asphaltic
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Posttensioning concrete has been developed for the runway surface.
This permits the use of thinner pavements and should result in longer
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Runway pavement surface is prepared and maintained to maximise
friction for wheel braking. To minimize [128]hydroplaning following
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[130]FAA airport diagram at O'Hare International Airport. From left to
right, runways 14/32 slant down, runways 4/22 slant up, and runways
9/27 are horizontal.
[131]FAA airport diagram at [132]O'Hare International Airport. From
left to right, runways 14/32 slant down, runways 4/22 slant up, and
runways 9/27 are horizontal.
The active runway is the runway at an [133]airport that is in current
use for [134]takeoffs and [135]landings. Since takeoffs and landings
are usually done as close to "into the [136]wind" as possible, wind
direction generally determines the active runway (or just the active
in aviation [137]slang).
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factors. At a [138]non-towered airport, pilots usually select the
runway most nearly aligned with the wind, but they are not obliged to
use that particular runway. For example, a pilot arriving from the
east may elect to land straight in to an east-west runway despite a
minor tailwind or significant crosswind, in order to expedite his
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supervisor. However, there may be constraints, such as policy from the
airport manager (calm wind runway selection, for example, or noise
abatement guidelines) that dictate an active runway selection that
isn't the one most nearly aligned with the wind.
At major airports with multiple runways, the active could be any of a
number of runways. For example, when O'Hare (ORD) is landing on 27R
and 32L, departures use 27L and 32R, thus making four active runways.
When they're landing on 14R and 22R, departures use 22L and 9L, and
occasionally a third arrival runway, 14L, will be employed, bringing
the active runway count to five.
At major airports, the active runway is based on existing weather
conditions (visibility and ceiling, as well as wind, and runway
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more aircraft on 14R-22R than they can on 27R-32L), traffic demand
(when a heavy departure rush is scheduled, a runway configuration that
optimizes departures vs arrivals may be desirable), and time of day
(ORD is obliged to use Runway 9L/27R during the hours of roughly
midnight to 6 a.m. due to noise abatement).
[[139]edit] Longest runways
Main article: [140]List of longest runways
Although runway length may be of some academic interest, in terms of
usability for [141]air carrier operations, a runway of at least
6,000 ft (1,829 m) in length is usually adequate for [142]aircraft