Editing Runway (section)

==Lighting==
[[File:Runway Landing Light.jpg|thumb|upright|A runway landing light from 1945]]

A line of lights on an airfield or elsewhere to guide aircraft in taking off or coming in to land or an illuminated runway is sometimes also known as a [[Approach lighting system|flare path]].

===Technical specifications===
<!-- Disambiguation pages and redirects link to this section. --><!-- Which ones? They're supposed to be listed here. -->
[[File:A320-cockpit-night.jpg|thumb|Night runway view from [[Airbus A320|A320]] cockpit]]
[[File:Bremen Airport Flugtag 2009 20090510 011.JPG|thumb|Ground light at [[Bremen Airport]]]]

Runway lighting is used at airports during periods of darkness and low visibility. Seen from the air, runway lights form an outline of the runway. A runway may have some or all of the following:<ref name="annex14e3">{{cite web
 |url         = http://legacy.icao.int/fsix/_Library%5CManual%20Aerodrome%20Stds.pdf
 |title       = Aerodrome Design and Operations
 |date        = July 1999
 |edition     = 3
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20120723004923/http://legacy.icao.int/fsix/_Library/Manual%20Aerodrome%20Stds.pdf
 |archive-date = 2012-07-23
}}</ref>
* '''[[Runway end identifier 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.
* '''[[Runway edge lights]]''' – white elevated lights that run the length of the runway on either side. On precision instrument runways, the edge-lighting becomes amber in the last {{convert|2000|ft|abbr=on|0}} of the runway, or last third of the runway, whichever is less. Taxiways are differentiated by being bordered by blue lights, or by having green center lights, depending on the width of the taxiway, and the complexity of the taxi pattern.
* '''Runway centerline lighting system''' (RCLS) – lights embedded into the surface of the runway at {{convert|50|ft|abbr=on|0}} intervals along the runway centerline on some precision instrument runways. White except the last {{convert|900|m|abbr=on}}: alternate white and red for next {{convert|600|m|ft|abbr=on|0}} and red for last {{convert|300|m|ft|abbr=on|0}}.<ref name="annex14e3"/>
* '''Touchdown zone lights''' (TDZL<ref name="Contractions" />) – rows of white light bars (with three in each row) at {{Convert|30|or|60|m|abbr=on}} intervals on either side of the centerline for {{convert|900|m|abbr=on}}.<ref name="annex14e3"/>
* '''Taxiway centerline lead-off lights''' – installed along lead-off markings, alternate green and yellow lights embedded into the runway pavement. It starts with green light at about the runway centerline to the position of first centerline light beyond the Hold-Short markings on the taxiway.
* '''Taxiway centerline lead-on lights''' – installed the same way as taxiway centerline lead-off Lights, but directing airplane traffic in the opposite direction.
* '''Land and hold short lights''' – a row of white pulsating lights installed across the runway to indicate hold short position on some runways that are facilitating [[land and hold short operations]] (LAHSO).<ref name="annex14e3"/>
* '''[[Approach lighting system]]''' (ALS) – a lighting system installed on the approach end of an airport runway and consists of a series of lightbars, [[strobe light]]s, or a combination of the two that extends outward from the runway end.

According to [[Transport Canada]]'s regulations,<ref>{{cite web
 |url         = http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-aga-7-0-3097.htm#aga-7-8
 |title       = §7.8 Runway Lighting
 |work        = TP 14371: Transport Canada Aeronautical Information Manual
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20130322045731/http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-aga-7-0-3097.htm#aga-7-8
 |archive-date = 2013-03-22
}}</ref> the runway-edge lighting must be visible for at least {{convert|2|mi|abbr=on|0}}. Additionally, a new system of advisory lighting, [[runway status lights]], is currently being tested in the United States.<ref>{{Citation
 |title       = FAA Installs Runway Safety Warning System at LAX
 |url         = http://www.faa.gov/news/press_releases/news_story.cfm?newsId=10609
 |access-date  = 2010-05-14
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20110606185538/http://www.faa.gov/news/press_releases/news_story.cfm?newsId=10609
 |archive-date = 2011-06-06
}}</ref>

The edge lights must be arranged such that:
* the minimum distance between lines is {{convert|75|ft|abbr=on|0}}, and maximum is {{convert|200|ft|abbr=on|0}}
* the maximum distance between lights within each line is {{convert|200|ft|abbr=on|0}}
* the minimum length of parallel lines is {{convert|1400|ft|abbr=on|0}}
* the minimum number of lights in the line is 8.<ref>[http://www.tc.gc.ca/CivilAviation/publications/tp14371/AGA/7-1.htm#7-8 Transport Canada Aeronautical Information Manual] {{webarchive|url=https://web.archive.org/web/20080617185432/http://www.tc.gc.ca/CivilAviation/publications/tp14371/AGA/7-1.htm |date=2008-06-17 }}</ref>
[[File:APPROACH LIGHTS AT BERLIN TEGEL AIRPORT WITH AN AIR UKRAINE BOEING 737-400 TAKING OFF BERLIN GERMANY JUNE 2013 (9023668647).jpg|thumb|[[Approach lighting system]] at [[Berlin Tegel Airport]]]]

===Control of lighting system===
Typically the lights are controlled by a [[control tower]], a [[flight service station]] or another designated authority. Some airports/airfields (particularly [[Non-towered airport|uncontrolled ones]]) are equipped with [[pilot-controlled lighting]], so that pilots can temporarily turn on the lights when the relevant authority is not available.<ref>{{cite web
 |url         = http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-aga-7-0-3097.htm#aga-7-18
 |title       = §7.18 Aircraft Radio Control of Aerodrome Lighting
 |work        = TP 14371: Transport Canada Aeronautical Information Manual
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20130322045731/http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-aga-7-0-3097.htm#aga-7-18
 |archive-date = 2013-03-22
}}</ref> This avoids the need for automatic systems or staff to turn the lights on at night or in other low visibility situations. This 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 may be nothing more than a [[windsock]] beside a landing strip.