
How aircraft avoid mid-air collisions - michaelrkn
https://www.economist.com/blogs/economist-explains/2018/04/economist-explains
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gizmodo59
This site upsets me. I'm viewing this page on a 32 inch monitor and I can only
see 8 lines of content. [https://imgur.com/a/EAMYr](https://imgur.com/a/EAMYr)

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ibdf
At least you get to read... apparently I have gone over my article limit even
though I don't recall ever being on this site.

I see a paywall. I close the tab. No news is too important that I can't go
without or find it somewhere else.

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mcguire
[https://screenshots.firefox.com/CRxzfF7mvaXZPYNJ/www.economi...](https://screenshots.firefox.com/CRxzfF7mvaXZPYNJ/www.economist.com)

Holy sweet mother of ....

I'm sure there's an article in there somewhere.

[Edit] Actually, no, I've reached my limit and been cut off.

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radicaldreamer
And this is why people use adblockers...

[https://www.dropbox.com/s/2u3o216xe8fho4o/Screenshot%202018-...](https://www.dropbox.com/s/2u3o216xe8fho4o/Screenshot%202018-04-03%2011.03.57.png?dl=0)

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jonknee
Oh, the irony:

[https://i.imgur.com/KVGwGCt.png](https://i.imgur.com/KVGwGCt.png)

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einrealist
Couldn‘t even see the „No, thanks“ on my iPad. Dark pattern by accident?

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chris_va
ADS-B is not a great solution, the latency/accuracy is such that you might
know a drone is in the area, but seeing it and avoiding would be difficult.
It's a lot easier to spot a small plane than it is to spot a drone.

As a pilot, I have had to avoid large birds more often than drones. They tend
to actively avoid planes, which helps. Some sort of active avoidance, even
super-minimal, on the part of the drones is likely to be more effective in
reducing accidents.

Just my 2 cents.

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markab21
I have only flown past what I believe seemed to have maybe been a drone
(honestly, it could of been a bird but I swear it looked like a drone to me).
I was taking off out of the Tampa airspace at about 1k feet AGL. If the drone
did have ADS-B out, it might not give me the precise location to where i can
do a 200' flyby, but just like any other aircraft avoidance, I could steer
clear of the general area where it's at and at least know that there is
something there.

My experience with ADS-B has been incredibly positive, I fly frequently in-
and-out of the Tampa bravo, being my home airport and love the situational
awareness. Sure it's not perfect but seems to be reasonably solid.

The biggest risk of having ADS-B is probably assuming there is nothing else
out there if it's not showing up on traffic.

I'm not an expert on this matter, simply a consumer of the tech as a pilot
myself. Regardless, it's interesting to listen to other pilots take on ADS-B.
= )

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korethr
I recall reading a proposal about this before, and I'll echo it here. There's
already a solution to avoid aircraft collisions, mentioned in the article:
ADS-B. Why not equip drones with ADS-B transceivers, enabling both drones and
planes to be aware of each other's presence and avoid one another?

A counter argument I can anticipate is that with all those drones in the air,
broadcasting ADS-B, they will clog up the system with too many signals. Those
who make the argument aren't wrong. I propose a solution for that as well:
reduced transmission power on drone ADS-B transceivers. Small craft have a
minimum transmission power of 75W, and craft that can fly over 15000 ft or
faster than 175 kt have to transmit at at least 125W. Few drones are going to
be moving that fast or that high. So why not make them have say, a
transmission power of 1W? I'd think that would be enough power to warn planes
on approach to an airport to watch out for nearby drones, without clogging up
the system with useless noise about drones the next city over.

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nradov
ADS-B alone is insufficient for collision avoidance. In order to operate
safely outside of special restricted airspace, drones would need to be able to
visually see and avoid other aircraft.

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sokoloff
(agreeing and amplifying)

ADS-B out is only mandated in an extremely limited subset of the airspace
where drones will be likely flying (and then only after Jan 1, 2020).

ADS-B out is only mandated[1] in cylinders around class C and the 30nm ring
around class B airports, in class A airspace (at/above 18000' MSL), and in
class E airspace that is both above 10000' MSL and 2500' AGL.

In practice, that means that most of the volume of drone-navigable airspace
does not require other aircraft to have ADS-B out transmitters.

In _none_ of the airspace are other aircraft required to have ADS-B _in_
receivers.

"See and avoid" is therefore both practically and legally[2] required.

[1] - 14 CFR § 91.225 -
[https://www.law.cornell.edu/cfr/text/14/91.225](https://www.law.cornell.edu/cfr/text/14/91.225)

[2] - 14 CFR § 91.113 -
[https://www.law.cornell.edu/cfr/text/14/91.113](https://www.law.cornell.edu/cfr/text/14/91.113)

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jacobreg
Not to mention even in all those areas (except A and B airspace), there are
still aircraft exempt from the ADS-B requirement. The mandate only applies to
aircraft certificated with an engine driven electrical system, so gliders and
piper cubs and those sorts of aircraft will still need see and avoid.

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Syzygies
After the mid-air collision over Brazil in 2006
([https://www.nytimes.com/2006/10/03/business/03road.html](https://www.nytimes.com/2006/10/03/business/03road.html))
I corresponded with a well-known pilot columnist. We didn't agree. I revealed
myself to be a mathematician, and he revealed himself to be exactly the
conformist one hopes a pilot following rules will be.

I observe planes holding their assigned altitudes to very close tolerances. It
strikes me as completely idiotic to quantize these altitudes independent of
heading, rather than scaling 360 degrees to 2000 feet (or pick your favorite
modern units) and adding one's heading to base altitudes. Then planes won't
cross each other's paths on a giving heading, avoiding accidents like Brazil.

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godelski
Your suggestion would kill GA (general aviation) if you had to fly a specific
altitude for a given direction. A good gust and a rusty pilot could rise or
fall a couple hundred feet pretty easily. Size of the plane matters a lot too.
Plus, what altimeter setting are you using? (What is 2000 ft? AGL? MSL?
Pressure altitude?) You would also frequently be required to violate these
altitudes to maintain VFR conditions because clouds are moving into your
airspace. And how do you do something like circling a point? How do you enter
a traffic pattern? You would hit task saturation in no time.

I say this as a math lover (physics degree holding) and a pilot. Currently we
have a rule; "Odd pilots fly East", so you could be 3500,5500,7500, etc. Going
west at 2500,4500,6500, etc. Everyone should also be using flight following
for anything but a really short flight. And flight following is really going
to help with collision avoidance.

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lutorm
Presumably this would only apply in class A airspace above 18,000 MSL. No one
hand-flies there anyway.

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_s
Recommended above 3000’ in all airspaces unless you’re in a pattern or CTA
then you follow ATC.

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sorenn111
I once read somewhere that birds naturally evolved to always veer to the right
to avoid collisions.

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markab21
In my experience flying, when you have one that is in your vision it's usually
too late to make drastic changes. Birds in our area tend to dive when we are
approaching them, if you see a bird above you it makes me very nervous. It
never stops surprising me how little I seem to be able to do when I do see a
bird, maybe a small nudge on the yoke. Also short final or just after rotation
on takeoff seems to be where i've had most of my near-misses with them.

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godelski
They love those runways. I have some pipers that just love to sit on the keys.
Freaks me out every time.

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markab21
One of my closest strikes was taking off from RW9 at Keywest one morning.
Scared the daylights out of me. Flying out of there at night is not only
daunting because of the darkness over the water after turning north but not
knowing if there are birds waiting for me in the air. :P

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tmuir
The paywall prevents me from finding out the economist's theory, but I can put
forth my own.

The two movies Sully and Deepwater Horizon, which both came out in 2016, are
near mirror images of each other in many ways.

Sully is partly the story about a pilot who has spent his entire career
landing failing airplanes, effectively training him to do it again with higher
stakes, where its never happened before. But its also the story of all of the
regulation that has prevented all commercial aviation disasters since 2001.
Sully may stay calm under pressure, but he's standing on the shoulders of
giants. The flight attendants stick to their training. The port authority and
the captains of the boats that rescue all of the passengers stick to their
training. The NTSB even sticks to their training in certain ways. Plans were
set forth, and followed. Even at the end of the movie, it is made clear that
the NTSB's flaw was to control for all of the time constraints Sullenberger
faced, all of the stress, and hid the fact that it was something like the 20th
attempt in the simulator that was the first successful landing.

Deepwater horizon is the story about a company that has successfully captured
their regulatory framework. There was inadequate training, inadequate safety
measures, inadequate equipment to properly measure the specifics of the well.
And so when the shit hits the fan, does everyone stay calm and exercise the
plan to effect their continued survival? Nope, they all panic, and they nearly
all die.

Planes and Trains are far safer than automobiles because of ratio of humans to
engines.

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nkurz
As a public service notice, all of your comments for the last week or so are
marked as dead. Some people like me view with show-dead on, and see them, but
most people don't. I've vouched for a few of them as I come across them, but
you might consider discussing the matter with hn@ycombinator.com. For what
it's worth, my personal opinion is that some of your comments like this one
are great, but it would be nice if you could be less confrontational in some
of your others.

~~~
tmuir
I've assumed that. I appreciate the advice. I got a little heated in the
Berkeley Study article this week. I guess I get to a point when some things
are plain as day to me, such as "Humans learn better when they are more awake
than less awake", and then read people pontificate about how this is such a
profound insight, and confirms a hunch they've had their whole life. Its like
I can see myself getting wound up, but I can't resist correcting my
detractors. It only get's worse when people can enumerate the trees, but roll
their eyes at others claiming a forest.

I even knew going into my final retort to /u/dang that he'd swing the
banhammer. But something in the back of my mind just said "hold my beer".

I fully agree that honey kills more flies than vinegar. But I'm also a Lord of
the Rings fan. Pip and Merri only convince the Ents to go to war through
forcing them to confront the clear cut forest. It was the Ents position, much
like the US before WWI, that this too shall pass, and we shouldn't involve
ourselves in the affairs of men/europe.

I'm not saying confrontation is always defensible, but its also not always
indefensible.

I guess I struggle at picking my battles.

