This already exists. Runway is lit up in white, has a green strip of lights at the close end as you look at it, and instrument rated fields have a chase strobe that points right to the end of the runway. Taxi ways are blue.

Things like this are being tried. SeaTac airport has a taxiway which is large, parallel, and frequently (enough) mistaken for a runway.

> SEA-TAC personnel have been very proactive in trying to reduce the problem, including the installation of an unlit, nonreflective elevated lighted X at the threshold of taxiway Tango; broadcasting a notice on the Automatic Terminal Information Service (ATIS) not to mistake the parallel taxiway for the adjacent runway; posting warnings on aeronautical charts not to mistake the taxiway for runway 16R; and the development of numerous training aids and brochures that explain the problem to transient pilots traveling through SEA-TAC.

(Testing of multiple methods begins on page 5)

http://www.airtech.tc.faa.gov/safety/downloads/TN07-54.pdf

"...including the installation of an unlit, nonreflective elevated lighted X at the threshold of taxiway Tango..."

Unlit lighted X. Right.

My assumption based on nothing in particular is that one (of unlit/lighted) means 'Lights contained within the X illuminating it from within' and the other means 'Lights external to the X illuminating it from without'

It is done pretty much like that. PDF warning, page 31: https://www.faa.gov/airports/southern/airport_safety/part139...

Taxiways are marked with blue lights.

Here's a video of a night landing on the same runway, the approach lighting is unmistakable: https://www.youtube.com/watch?v=rNMtMYUGjnQ

Yeah. At 1:18 that's clearly HIRL enabled. There's no ambiguity that's for a runway rather than taxiway. And it's not possible to visually misalign yourself with the taxiway, the whole point of HIRL is a visual aid for precision instrument landings in bad weather for Cat I and II ILS landings. On an instrument landing, it's not legal to go below decision height (200 and 100 feet respectively) unless you meet the visual reference requirement in 91.175 c3, ergo the HIRL lighting is simply unambiguous for a night VFR landing, and makes me wonder if it was even on.

this sounds like the start of a good idea, but we should choose something that works for colorblind people and red/green colorblind people too.

Stupid question - can you be certified as a commercial pilot if you are colourblind?

No, you can't. A friend of mine couldn't become a commercial pilot because he has some kind of colourblindness.

However, I remember him trying for some time and even campaigning for colourblind people to be admissible as commercial pilots because for the actual flying colourblindness doesn't seem to matter.

So, perhaps ridiculous as it may sound taking colourblindness into account when proposing such an improvement isn't such a weird idea after all.

You can become color blind later though.

Commercial pilots are generally required to take a regular medical (it's every 6 months or 12 months in the UK).

If a pilot were to acquire colour blindness, they'd be obliged to ground themselves and report the condition to the aviation authority.

Or temporarily from medication, particularly those used to treat erectile dysfunction and benign prostatic hyperplasia [1][2].

[1] https://www.faa.gov/about/office_org/headquarters_offices/av...

[2] https://www.leftseat.com/viagra.htm

... and as a professional pilot, you'd probably have to consult a flight physician if you were taking meds like these.

Actually, airline pilots (and pilots generally) are not the only people you need to take into account here. Many other potential users of the runways and taxiways would need to be taken into account, including ground staff and maintenance staff. Since I doubt that all of these are ruled out on the basis of colourblindness, it makes sense to construct a system that is impervious to ambiguity due to colourblindness.

But ground and maintenance staff don't need to identify them by colour from far away. For them, you could rely on simple signage.

Not a stupid question at all. I clearly remember doing the colour blind test during my preliminary medical when I arrived at flying school to get my commercial licence.

The test consists of going through a book with images made up of different coloured dots, and within each image was a coloured number made up of similar dots. We simply had to flip through the book and identify the number within each image.

I was totally smug as I flipped through the book, calling out the numbers and watching the doctor tick off his chart. But towards the end of the booklet, I reached a page, and the image was just a jumble of dots to me. I couldn't see a number. I remember the panic and tightening in my chest as I thought to myself "Oh No, I can't see the number - I MUST be colour blind!! My dream of being a pilot is OVER".

I stared and stared at the page, but in the end had to concede defeat and I quietly told the doc that I couldn't see the number on that page. "Oh", he replied casually. "That's OK, there isn't one on that page!". And he grabbed the booklet and tossed it back on his desk saying "You passed."

Yes, but the certificate comes with a limitation (color signal landing daytime only proscription; or night and color signal landing proscription).

The requirements vary depending on class of medical certificate but in this context it's a class I medical for airline transport pilots (not commercial pilots) so it's complicated.

Also, full on dichromats or monochromats are rare. Usually people are one of three anomalous trichomats. Hence testing is required to determine if it's a problem. The initial test is designed to have a high failure rate, and the exception tests to get the restrictions lifted take more effort.

https://www.aopa.org/go-fly/medical-resources/health-conditi...

You can’t even be certificated as a Private Pilot if you are colorblind.

Not true at all.

https://www.aopa.org/go-fly/medical-resources/health-conditi...

Why do people comment on things they know nothing about? Of course you can.

It's HN.... I get a good laugh out of all these aviation related threads. Understandably your average CS undergrad doesn't have much real aeronautical knowledge but that doesn't stop everyone from blowing up the comments every time the word 'airplane' is uttered.

You can, but you're not allowed to fly at night.

No you just get a night flying and color signals proscription on your certificate if you're a monochromat or dichromat (full color blindness); if you merely have a color discrimination problem by being an anomalous trichromat, you might pass the test, or fail it but then get an exemption (reversal of the prior failure) by later passing a more involve series of tests.

My father is red-green colorblind and he flies small planes.