Editing Runway (section)

===Naming===
[[File:Runway 22.svg|thumb|left|upright|Runway 22]]
[[File:Runway landing designator marking-Numbers.svg|thumb|upright|left|Font and size of numbers and letters]]

Runways are named by a number between 01 and 36, which is generally the [[Compass#How a magnetic compass works|magnetic]] [[azimuth]] of the runway's [[heading (navigation)|heading]] in [[deca-|deca]][[Degree (angle)|degrees]]. This heading differs from [[true north]] by the local [[magnetic declination]]. A runway numbered 09 points east (90°), runway 18 is south (180°), runway 27 points west (270°) and runway 36 points to the north (360° rather than 0°).<ref>[http://www.faa.gov/air_traffic/publications/ATpubs/AIM/Chap2/aim0203.html Federal Aviation Administration Aeronautical Information Manual, Chapter 2, Section 3 Airport Marking Aids and Signs part 3b] {{webarchive|url=https://web.archive.org/web/20120118165015/http://www.faa.gov/air_traffic/publications/atpubs/aim/Chap2/aim0203.html |date=2012-01-18 }}</ref> When taking off from or landing on runway 09, a plane is heading around 90° (east). A runway can normally be used in both directions, and is named for each direction separately: e.g., "runway 15" in one direction is "runway 33" when used in the other. The two numbers differ by 18 (= 180°). For clarity in radio communications, each digit in the runway name is pronounced individually: runway one-five, runway three-three, etc. (instead of "fifteen" or "thirty-three").

[[File:ORD Airport Diagram.svg|thumb|upright|[[FAA]] airport diagram at [[O'Hare International Airport]]. The two 14/32 runways go from upper left to lower right, the two 4/22 runways go from lower left to upper right, and the two 9/27 and three 10/28 runways are horizontal.]]
A leading zero, for example in "runway zero-six" or "runway zero-one-left", is included for all ICAO and some [[United States armed forces|U.S.&nbsp;military]] airports (such as [[Edwards Air Force Base]]). However, most U.S.&nbsp;[[civil aviation]] airports drop the leading zero as required by FAA regulation.<ref>{{cite book | title = FAA Advisory Circular AC 150/5340-1L - Standards for Airport Markings | chapter=Chapter 2.3.e.(2) | chapter-url = http://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1022266 | page=17 | quote=A single-digit runway landing designation number is never preceded by a zero.}}</ref> This also includes some military airfields such as [[Cairns Army Airfield]]. This American anomaly may lead to inconsistencies in conversations between American pilots and controllers in other countries.

Military airbases may include smaller paved runways known as "assault strips" for practice and training next to larger primary runways.<ref>{{Cite web|url=https://www.amc.af.mil/News/Article-Display/Article/146910/new-assault-landing-strip-opens-in-wyoming-mcchord-c-17-makes-first-landing/|title=New assault landing strip opens in Wyoming; McChord C-17 makes first landing}}</ref> These strips eschew the standard numerical naming convention and instead employ the runway's full three digit heading; examples include [[Dobbins Air Reserve Base]]'s Runway 110/290	and [[Duke Field]]'s Runway 180/360.<ref>{{cite web|title=Duke Field (Eglin AF Aux Nr 3) Airport|publisher=Airnav.com|date=July 16, 2020|url=https://www.airnav.com/airport/KMGE|access-date=August 5, 2020}}</ref><ref>{{cite web|title=Dobbins Air Reserve Base|publisher=Airnav.com|date=July 16, 2020|url=https://www.airnav.com/airport/KEGI|access-date=August 5, 2020}}</ref>

Runways with non-hard surfaces, such as small turf airfields and waterways for [[seaplane]]s, may use the standard numerical scheme or may use traditional [[Compass rose|compass point]] naming, examples include [[Ketchikan Harbor Seaplane Base]]'s Waterway E/W.<ref>{{cite web|title=Ketchikan Harbor Seaplane Base
|publisher=Airnav.com|date=July 16, 2020|url=https://www.airnav.com/airport/5KE|access-date=August 8, 2020}}</ref><ref name=ac15035/> Airports with unpredictable or chaotic water currents, such as [[Santa Catalina Island (California)|Santa Catalina Island]]'s Pebbly Beach Seaplane Base, may designate their landing area as Waterway ALL/WAY to denote the lack of designated landing direction.<ref>{{cite web|title=Pebbly Beach Seaplane Base|publisher=Airnav.com|date=July 16, 2020|url=https://www.airnav.com/airport/L11|access-date=August 5, 2020}}</ref><ref name=ac15035/>