
The Hidden Beauty of Airport Runways, and How to Decipher Them  - ghosh
http://www.wired.com/2014/05/the-hidden-beauty-of-airport-runways-and-how-to-decipher-them/
======
davidwihl
Chevrons do not "mark the direction of a given strip". Imagine chevrons
pointed toward grass and rock instead of the runway - what sane pilot would
follow that instead of the pavement?

Chevrons "are used to show pavement areas aligned with the runway that are
unusable for landing, takeoff, and taxiing." [1] In other words, the pavement
is too soft to bear a heavy load.

[1]
[https://www.faa.gov/air_traffic/publications/atpubs/aim/aim0...](https://www.faa.gov/air_traffic/publications/atpubs/aim/aim0203.html#aim0203.html.1)

~~~
omegant
As a side note, sometimes they are painted to move forward the runway
beginning. The runway itself it´s still hard and usable, but they want you to
land and takeoff further ahead from the real beginning, to reduce the noise at
the proximity of the airport and the approach route (the planes flight higher
at a given point if you move forward the runway)

~~~
cjrp
That would be a displaced threshold, marked with arrows rather than chevrons.
Can be used for takeoff but not for landing (usually to ensure obstruction
clearance on the approach).

~~~
sokoloff
Correct.

In the article's photo of Logan, you can see both on 22L. The chevrons mark an
area not usable for either takeoff or landing on 22L. Then, the section marked
with a series of 5 long arrows is usable for taking off from 22L, leading to
the displaced threshold, beyond which the runway surface is usable for landing
(and takeoff, of course).

The displaced thresholds on 22L and 22R at Logan are to ensure adequate
clearance over boats in the channel north of the field.

More info for the curious, from the FAA Airmen's Information Manual:
[http://www.faa.gov/air_traffic/publications/atpubs/aim/aim02...](http://www.faa.gov/air_traffic/publications/atpubs/aim/aim0203.html)

------
asharpe
There is a beauty to a system that has been designed and implemented so
effectively where almost every example will be a unique deployment yet simply
work. There is a whole other layer of directions on the taxi ways that ensures
planes can keep moving and is standardised across all airports. Doesn't sound
like an important factor, but when the wind changes and you have to have all
planes take off (and land) in another direction ... and they don't have
reverse ...

------
danpalmer
At university we had a software development assignment designed to test our
ability to work in groups, stick to a process, etc, while building a large
(ish) piece of software.

The piece we were given was runway visualisation, every year it's a challenge
posed by the local airport, and it's always a fascinating glimpse into the
very complex world of airport standards. An example we encountered is the
volume designated as the 'runway' extends far beyond the concrete part, out
onto the surrounding grass which might be supported underneath, and further
out to unsupported grass.

------
smickie
I can't remember where I read this but the font they write on the roads (at
least in the UK) when looked at straight-on seems unusually tall, but when
viewed from the steep angle of a car it looks normal sized.

I would guess the same is true with these numbers, when a pilot is taxing
around the runway the font won't look as tall because of the extreme angle of
viewing from the cockpit.

------
sramsay
I was really hoping this article would explain the signs you see as you're
taxi-ing around. I've always wondered what system is at work there, since
they're clearly not simple "road signs" (as in, "this way to runway 18").

~~~
sokoloff
Here's the Airmen's Information Manual link to the signage:
[http://www.faa.gov/air_traffic/publications/atpubs/aim/aim02...](http://www.faa.gov/air_traffic/publications/atpubs/aim/aim0203.html)

The signage doesn't stand alone. You get directions from "Ground" (the ATC
position in charge of the movement areas other than the runway):

"<Aircraft>, Taxi [to] Runway XX via [taxiways] A, Q, M3, hold short [of]
runway YY." You also have taxiway charts (paper or electronic).

So, there isn't much to discern about the signage other than "You are on
taxiway X" vs "You are approaching taxiway Y [or runway Z" vs "Here is the
hold line for purpose P", but there isn't any systematic way to know how to
get to runway 18 without the airport diagram or directions from ATC.

------
personlurking
Article based on this Tumblr [http://holding-
pattern.tumblr.com/](http://holding-pattern.tumblr.com/)

------
minikomi
The Hidden Utility of Browser Back Buttons, and How to Deceive Them

~~~
coldpie
Noscript, as usual, improves javascript-heavy pages.

------
liotier
This begs for a "runway designators" font - would look great for aeronautical
or technical titles !

~~~
akx
The font isn't very aesthetically pleasing, though.

Almost a prime example of function over form, heh. :)

~~~
dalke
I knew a pilot who installed the blue lights used for airfield taxiways
alongside his driveway. He said that when flying, the blue lights meant that
he was almost done and could soon relax. He wanted that feeling when he was
coming home.

There are many people in the world. I can well imagine that some want the
associations that that font might bring.

------
ordinary
Is it just me or is that font a mess? The insides of the '11' are 3.8m apart.
Adding the overhang of the second 1 (0.3m) and the width of the vertical lines
of both 1s (2 * 0.8m) gives us 5.7m. Yet the outsides measurement is displayed
as 5.6m.

Same for the 10: Adding up the space between the characters (2.3m), the width
of the 1 (0.8m, just the vertical line) and the width of the 0 (3m) gives us
6.1m, yet the outside measurement is 6.0m.

Am I missing something?

~~~
DrJokepu
Yeah the numbers don't quite add up; I reckon it's something like the original
standard was in imperial units that was converted to metric later and at some
point someone somewhere (possibly a journalist) decided to round the numbers
without making sure they add up.

------
Serow225
I can't recall which runway marker I'm thinking of, but I know that there's
one that pilots refer to as 'the coffins' \- as in if you land past them,
you're in trouble... Obviously they don't call them that in front of pax ;)

~~~
mikeash
That doesn't make too much sense, as runways vary enormously in length, and
airplanes vary enormously in how much space they need to land.

A loaded-up B-52 landing in no wind on a 5,000ft runway needs to touch down
right at the beginning and even then it's going to be touchy. On the other
hand, I could land my ASW-20 in a 20kt headwind 14,800ft down a 15,000ft
runway and be entirely comfortable.

Of course, everybody tries to land near the beginning because it increases
your margin for error, but it's not strictly necessary in many situations.

------
lighthazard
Is that a 9 or 6?

~~~
cjrp
They're marked as 06 or 09, and it's impossible to have runways 60 or 90 so
would be hard to make that mistake.

~~~
brk
For those that wonder why it's impossible...

Runway numeric designators are the compass heading of the runway, divided by
10.

So, Runway 27 would be a runway oriented at 270 degrees. The other end of that
runway would be runway 9 (It's 180 degrees the opposite direction, 18 lower).

Therefore, a runway 60 would indicate 600 degrees, on a 360 degree arc ... :)

~~~
falcolas
More compass and runway fun - magnetic north moves over time, so a runway's
number may change over time, despite not moving.

~~~
sokoloff
More random trivia. Runways are not strictly named by their magnetic headings.

Chicago O'Hare has so many east-west runways that they have "mis-named" some
of them: (see 10L/28R and 10C/28C, both of which are on magnetic headings of
93/273\. And yes, they have a 10-Left and 10-Center, but no 10-Right. :))

[http://airnav.com/airport/ORD](http://airnav.com/airport/ORD)

~~~
falcolas
Sounds like a side effect of the magnetic north movement. It has drifted east
(in relation to the US) about 6° in the last 30 or so years, so if Chicago
hasn't re-named them since laying them down, a compass alignment of ~100°
becoming 93° makes sense.

~~~
sokoloff
No, it's the effect of having more than 3 east-west runways. 9L, 9R, 10L, and
10C.

The sub-names (left, center, right) only go up to 3.

Detroit Metro has the same issue with their SW/NE runways (21L, 21R, 22L, and
22R are all mutually parallel.)
[http://airnav.com/airport/dtw](http://airnav.com/airport/dtw)

Atlanta Hartsfield has 5 runways, all aligned on 94.4*, named 8L, 8R, 9L, 9R,
and 10:
[http://155.178.201.160/d-tpp/1405/00026AD.PDF](http://155.178.201.160/d-tpp/1405/00026AD.PDF)

