The Hidden Beauty of Airport Runways, and How to Decipher Them | Hacker News Reader

The Hidden Beauty of Airport Runways, and How to Decipher Them

wired.com

114 pointsghosh36 comments

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...

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)

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).

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...

The area may be an Engineered Material Arresting System. That is, an area of specially designed softness that slows an aircraft down really quickly without too much damage.

http://www.airportsinternational.com/2011/01/arresting-syste...

It also would be an blast pad - an area of pavement that is kept clean to prevent aircraft engines blowing dust and stones around when taking off.

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 ...

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.

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.

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").

Here's the Airmen's Information Manual link to the signage: http://www.faa.gov/air_traffic/publications/atpubs/aim/aim02...

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.

They are simply road signs, that say "this way to runway 18", "this way to taxy A", "this way is prohibited", or "you are in taxy A".

They are just very abbreviated in a standard code.

Article based on this Tumblr http://holding-pattern.tumblr.com/

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

Noscript, as usual, improves javascript-heavy pages.

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

The font isn't very aesthetically pleasing, though.

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

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.

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?

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.

Odd, I would have thought the 6 and 9 would not be reverse of each other, as in having one not use a slanted portion.

The font is defined graphically in a grid of 20cm divisions. The author probably measured those numbers with a ruler.

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 ;)

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.

Is that a 9 or 6?

Not a problem because the end of the runway is always down.

That, and they are surrounded by an entire lot of marks and arrows that will remove any remaining confusion.

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.

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 ... :)

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

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

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.

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

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

10R is actually under construction and will be open around October 2015. =)

When I started flying, my home airport had runway 09/27. A few years ago, it got repainted as 10/28 because of drift. Some people still slip up and call it 09/27 by accident.

Generally not the the US. Runways 1-9 are overwhelmingly labelled with a single digit in the US, and with a leading zero in most of the world.

Oh interesting, I assumed it was an ICAO standard or something. Cheers!

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