# Airport runway numbering **URL:** \ **Category:** Factual Questions\ **Created:** [June 27, 2008, 6:16am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408 "2008-06-27T06:16:37Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Chickenwrangler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chickenwrangler/32/91_2.png) [@Chickenwrangler](https://boards.straightdope.com/u/Chickenwrangler)\ **Post date:** [June 27, 2008, 6:16am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/1 "2008-06-27T06:16:37Z")
Often in movies we see the hero in the crippled plane being given instructions by ground control to use certain runway that has been cleared for him. How are these runways numbered? I would guess it has some connection with the orientation, degrees on the compass perhaps so the pilot has some idea of how to align his plane on approach. Having said that I have seen pictures of aircraft carriers with numbers on the end of the flight deck so the compass idea would not work, are flight decks numbered differently from runways? How are any of them numbered? (Yes I know they use paint) :rolleyes: CW. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [June 27, 2008, 6:27am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/2 "2008-06-27T06:27:41Z")
I dunno about aircraft carriers, but landlubber runways are numbered by their magnetic compass orientation, rounded to the nearest ten degrees, with the extraneous zero cut off. So a runway pointing at 120 degrees would be runway one-two. Runways can be used in both directions, so if you’re coming the other way, the same runway is now called runway three-zero (300 degrees.) If there are parallel runways, they’ll be named Left and Right. So two runways pointing 83 degrees would be called runway eight-left and eight-right. From the other direction, they’d be on opposite right/left sides, and so they’d be two-six-right and two-six-left. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [June 27, 2008, 6:47am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/3 "2008-06-27T06:47:58Z")
[QUOTE=Chickenwrangler] Having said that I have seen pictures of aircraft carriers with numbers on the end of the flight deck so the compass idea would not work, are flight decks numbered differently from runways? [/QUOTE] The numbers you see painted on a carrier is the number of the ship. For example, the USS Enterprise is CVN-65, and it has 65 painted on the deck. See [picture here](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/USS_Enterprise_%28CVN_65%29_underway.jpg/300px-USS_Enterprise_%28CVN_65%29_underway.jpg). ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [June 27, 2008, 7:47am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/4 "2008-06-27T07:47:06Z")
[QUOTE=t-bonham@scc.net] The numbers you see painted on a carrier is the number of the ship. For example, the USS Enterprise is CVN-65, and it has 65 painted on the deck. See [picture here](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/USS_Enterprise_%28CVN_65%29_underway.jpg/300px-USS_Enterprise_%28CVN_65%29_underway.jpg). [/QUOTE] Helpful, of course, so the pilot can make sure he is landing on the right ship. 😃 I don’t know if it’s still the case, but it used to be that aircraft carriers were always sailing directly into the wind when launching or recovering planes, so the aircraft could take advantage of the headwind to either maximise their airspeed on takeoff (if the windspeed is a brisk 10 knots, and the ship is traveling at 20 knots, you already have 30 knots of airspeed before you start rolling down the length of the ship) and to minimise the groundspeed on landing. Basically, the plane has to travel through the air at a minimum speed to stay aloft without crashing, so pilots always try to take off and land into the wind so they don’t need as much runway. Generally speaking, runways at airports are laid out so they point into the prevailing winds for the area, and whichever runway points into the wind at a given moment is the one primarily used. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [June 27, 2008, 8:55am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/5 "2008-06-27T08:55:00Z")
[QUOTE=friedo] If there are parallel runways, they’ll be named Left and Right. So two runways pointing 83 degrees would be called runway eight-left and eight-right. From the other direction, they’d be on opposite right/left sides, and so they’d be two-six-right and two-six-left. [/QUOTE] What happens if there are three parallel runways? Pearson Airport in Toronto has three parallel runways pointing roughly east-west and two pointing roughly north-south. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [June 27, 2008, 12:25pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/6 "2008-06-27T12:25:20Z")
[QUOTE=Sunspace] What happens if there are three parallel runways? Pearson Airport in Toronto has three parallel runways pointing roughly east-west and two pointing roughly north-south. [/QUOTE] The center runway is called Center. In the case of Pearson Airport, though, the third runway is sufficiently far away that it gets a different number. You can see the runway designations in Google Maps: [Runways 06L and 06R](http://maps.google.com/maps?f=q&hl=en&geocode=&q=pearson+airport,+toronto&sll=42.44049,-76.49545&sspn=0.081203,0.10025&ie=UTF8&ll=43.660366,-79.62189&spn=0.004975,0.010428&t=h&z=17) [Runway 05](http://maps.google.com/maps?f=q&hl=en&geocode=&q=pearson+airport,+toronto&sll=42.44049,-76.49545&sspn=0.081203,0.10025&ie=UTF8&ll=43.674763,-79.662166&spn=0.004974,0.010428&t=h&z=17) I am unsure whether Runway 05 really is 10 degrees off from 06. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [June 27, 2008, 12:25pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/7 "2008-06-27T12:25:44Z")
[QUOTE=Sunspace] What happens if there are three parallel runways? Pearson Airport in Toronto has three parallel runways pointing roughly east-west and two pointing roughly north-south. [/QUOTE] According to [Wikipedia](http://en.wikipedia.org/wiki/Runway), you can use left, right and center. If you’ve got more than three, then you can use numbers close to the actual compass headings. For example, four parallel runways all pointing 65 degrees could be six-left, six-right, seven-left, and seven-right. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [June 27, 2008, 1:39pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/8 "2008-06-27T13:39:32Z")
At Sky Harbor Airport in Phoenix, the third runway was added much later on the other side of the terminal buildings so, from the east end of the runways from south to north, they’re numbered 25L, 25R and . . . 26 There is no discernable difference in the new runway’s orientation so I’m guessing they wanted to avoid renaming the old ‘R’ runway now finding itself in the middle. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [June 27, 2008, 2:28pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/9 "2008-06-27T14:28:45Z")
[QUOTE=Chickenwrangler] Often in movies we see the hero in the crippled plane being given instructions by ground control to use certain runway that has been cleared for him. How are these runways numbered? I would guess it has some connection with the orientation, degrees on the compass perhaps so the pilot has some idea of how to align his plane on approach. Having said that I have seen pictures of aircraft carriers with numbers on the end of the flight deck so the compass idea would not work, are flight decks numbered differently from runways? How are any of them numbered? (Yes I know they use paint) :rolleyes: CW. [/QUOTE] Do they use paint on aircraft carriers and runways??? :dubious: Sometimes they use that rubbery stuff (that’s the technical term). 😃 ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [June 27, 2008, 4:05pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/10 "2008-06-27T16:05:36Z")
I hesitate to use the term “hijack” in an airplane thread, so “slight change of subject”: How thick is a typical runway? And how about an aircraft carrier flight deck? ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [June 27, 2008, 4:49pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/11 "2008-06-27T16:49:24Z")
[QUOTE=Terminus Est] In the case of Pearson Airport, though, the third runway is sufficiently far away that it gets a different number. You can see the runway designations in Google Maps: [Runways 06L and 06R](http://maps.google.com/maps?f=q&hl=en&geocode=&q=pearson+airport,+toronto&sll=42.44049,-76.49545&sspn=0.081203,0.10025&ie=UTF8&ll=43.660366,-79.62189&spn=0.004975,0.010428&t=h&z=17) [Runway 05](http://maps.google.com/maps?f=q&hl=en&geocode=&q=pearson+airport,+toronto&sll=42.44049,-76.49545&sspn=0.081203,0.10025&ie=UTF8&ll=43.674763,-79.662166&spn=0.004974,0.010428&t=h&z=17) I am unsure whether Runway 05 really is 10 degrees off from 06. [/QUOTE] Ah, thanks! I’d forgotten that they put the numbers on the actual runways. 🙂 (Incidentally, those Google maps pictures of Pearson airport _really_ need to be updated. The part under construction has been open for well over a year, and the long straight terminal at the right has been closed and totally demolished. Also, quite a few of the roads have been removed.) ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [June 27, 2008, 5:00pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/12 "2008-06-27T17:00:27Z")
[QUOTE=Tom Tildrum] I hesitate to use the term “hijack” in an airplane thread, so “slight change of subject”: How thick is a typical runway? And how about an aircraft carrier flight deck? [/QUOTE] Do you mean how thick is the concrete or how wide is the runway? Runways are typically 150 feet wide. Incidentally, runways are numbered based on magnetic variation and as that changes they are renumbered. It can be an enlightening experience to fly into an airport where the numbers change and there are runways on similar headings (and you are using old information). ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [June 27, 2008, 5:18pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/13 "2008-06-27T17:18:43Z")
[QUOTE=Magiver] Do you mean how thick is the concrete or how wide is the runway? Runways are typically 150 feet wide. [/QUOTE] How thick is the concrete? Just curious. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [June 27, 2008, 5:26pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/14 "2008-06-27T17:26:45Z")
[http://www.boeing.com/commercial/airports/faqs/boeing\_pavement\_surface\_types.pdf](http://www.boeing.com/commercial/airports/faqs/boeing_pavement_surface_types.pdf) Rigid Pavement - A runway, taxiway, or ramp that is surfaced with a mixture of concrete materials (portland cement, sand, coarse aggregate, and water) of from 6 to 20 inches (15 to 51 centimeters) or more in thickness. Typical narrow body runways usually have 11 to 13 inches (28 to 33 centimeters) of concrete thickness, and runways that serve wide body aircraft usually have 17 to 20 inches (43 to 51 centimeters) of concrete thickness. This type of construction qualifies a runway to be referred to as “hard surfaced” or “paved”. (Also known as a “concrete” pavement.) ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [June 27, 2008, 5:33pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/15 "2008-06-27T17:33:21Z")
[QUOTE=Tom Tildrum] I hesitate to use the term “hijack” in an airplane thread, so “slight change of subject”: How thick is a typical runway? And how about an aircraft carrier flight deck? [/QUOTE] [http://www.cement.org/pavements/pv\_cp\_airports.asp](http://www.cement.org/pavements/pv_cp_airports.asp) > [@from link](#): > > Today, specifications for airport concrete pavement vary depending on subgrade conditions, expected loading, and anticipated pavement life-span. New concrete runways at non-hub airports generally range in thickness from 9 to 12 in. (22.5 to 30 cm), while runways at hub airports often are constructed 15 to 18 in. (37.5 to 45 cm) thick to withstand larger and more frequent loading. Aircraft carriers: The thickness will depend on what the designers wanted the flight deck to do, like resist bombs. Weight of aircraft to be operated is now a main concern, as modern missiles and bomb will penetrate any practical thickness of armor mounted that high up in the ship. Also, in modern U.S. carriers, the flight deck is used as a main structural support element for the ship, and the given thickness of the flight deck, using high grade steel, is for achieving that purpose. Unfortunately, I am having a problem prying this info out of the interwebz, and my reference books at home. :smack: If no one beats me to it, I will look up the info when I get home in a few hours. (I will WAG the thickness to be 2 or 3 inches on the Nimitz class.) ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [June 27, 2008, 10:07pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/16 "2008-06-27T22:07:10Z")
Unfortunately, my reference books do not give a flight deck thickness for the Nimitz class, sorry. ☹ ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [June 27, 2008, 11:26pm UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/17 "2008-06-27T23:26:25Z")
[QUOTE=Magiver] Do you mean how thick is the concrete or how wide is the runway? Runways are typically 150 feet wide. [/QUOTE] Also, another fun fact, IIRC, the short thick stripes you see on either side of the center line at the end of a runway indicate how wide the runway is. Each stripe means so many feet wide, IIRC, so pilots can get an easy visual reference to help judge their landing. ---
**Author:** ![KCB615](https://avatars.discourse-cdn.com/v4/letter/k/ea666f/32.png) [@KCB615](https://boards.straightdope.com/u/KCB615)\ **Post date:** [June 28, 2008, 3:05am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/18 "2008-06-28T03:05:58Z")
Regarding threshold bars and runway width: 60 feet (18 m) - 4 bars 75 feet (23 m) - 6 bars 100 feet (30 m) - 8 bars 150 feet (45 m) - 12 bars 200 feet (60 m) - 16 bars If you’re interested, everything (and I do mean everything) you ever wanted to know about marking of airport surfaces in the US is in this Advisory Circular: [http://www.faa.gov/airports\_airtraffic/airports/resources/advisory\_circulars/media/150-5340-1J/150\_5340\_1j.pdf](http://www.faa.gov/airports_airtraffic/airports/resources/advisory_circulars/media/150-5340-1J/150_5340_1j.pdf) Don’t read while driving or operating heavy machinery. ---
**Author:** ![FoieGrasIsEvil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foiegrasisevil/32/16638_2.png) [@FoieGrasIsEvil](https://boards.straightdope.com/u/FoieGrasIsEvil)\ **Post date:** [June 28, 2008, 3:14am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/19 "2008-06-28T03:14:34Z")
Do concrete runways at land-based airports get all potholed from the temperature changes and the constant pounding they take from landing aircraft? What’s the average lifespan of a runway’s concrete surface? ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [June 28, 2008, 5:13am UTC](https://boards.straightdope.com/t/airport-runway-numbering/454408/20 "2008-06-28T05:13:00Z")
[QUOTE=Magiver] Do you mean how thick is the concrete or how wide is the runway? Runways are typically 150 feet wide. Incidentally, runways are numbered based on magnetic variation and as that changes they are renumbered. It can be an enlightening experience to fly into an airport where the numbers change and there are runways on similar headings (and you are using old information). [/QUOTE] Do not ever admit or get caught using OLD information much less have an incident because of it. It is way illegal and the FAA takes a real dim view of it.