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?
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.
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.
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.
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.
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:
According to Wikipedia, 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.
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.
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.)
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).
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.)
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.)
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.
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:
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.
