
How odd is a cluster of plane accidents? - arb99
http://www.bbc.com/news/magazine-28481060
======
gleenn
I'm pretty happy someone actually wrote something about this, I was surprised
I didn't hear any news outlets talking about the connection beyond just
mentioning the other accident.

I'm also happy to see some at least slightly non-trivial statistics in the
mainstream.

One glaring point though: the liklihood of another crash might not be high
given whatever statistics, but those don't reflect the fact that _someone shot
a missile at one of those planes_. I might risk a flight in Africa or Taiwan
or where-ever, but you won't see me flying anywhere near Russia/Ukraine
anytime soon even though people obviously thought this was a perfectly
reasonable thing to do.

~~~
guard-of-terra
"but you won't see me flying anywhere near Russia/Ukraine anytime soon"

Actually most flights from Europe to East Asia fly over Russia now while
carefully avoiding Ukrainian airspace.

So if you really need there and want to avoid Russian airspace, you'll have to
fly via Africa or Americas or possibly transsiberian rail.

By glancing at flightradar24: Everybody is scared to fly over Ukraine, except
for Russian (Transaero) and some Turkish planes bound to Russia who fly over
central Ukraine just fine.

~~~
kaeawc
For reference:
[http://www.flightradar24.com/49.08,30.48/6](http://www.flightradar24.com/49.08,30.48/6)

~~~
gpmcadam
Quite interesting. When you zoom out slightly further you can see a very
visible avoidance of the entire country:
[http://puu.sh/ar1f4/b7231c1b24.png](http://puu.sh/ar1f4/b7231c1b24.png)

~~~
nawitus
There's now multiple Western airlines flying over Ukraine. Most planes simply
avoid the Eastern parts of Ukraine.

------
josephpmay
This article gives a great insight into the nature of randomness:

[http://www.wired.com/2012/12/what-does-randomness-look-
like/](http://www.wired.com/2012/12/what-does-randomness-look-like/)

~~~
xsace
That's the best thing I've read in days.

~~~
michaelmcmillan
I agree! That was an easy-to-read explanation of Poisson Distribution.

------
jameshart
I've always argued that clusters of plane accidents are reassuring signs that
they truly are random. If plane crashes happened with precise, predictable
regularity, once every three weeks, say, then that would be a sign that there
was some sort of terrible uncontrollable force at work in the world.

~~~
Someone
We thought solar eclipses and new moons were signs of terrible uncontrollable
forces, too, but we know better now.

AFAIK, we never thought that of solar maximums, so if plane crashes happened
every three weeks, I doubt we would think them signs of terrible forces.

Also, I would know when not to book a flight, as would everybody else.

~~~
jessaustin
_We thought solar eclipses and new moons were signs of terrible uncontrollable
forces, too, but we know better now._

I don't think that eclipses are in any sense "controllable".

------
mxfh
This paper argues it's a poisson distribution:

 _Time-evolving distribution of time lags between commercial airline
disasters_ [1]

while others disagree:

 _In the case of plane accidents, the authors of Ref. 7[1] found that the time
lag between commercial airline disasters and their occurrence frequency could
be well described by time-dependent Poisson events. On the other hand, authors
of Ref. 8[3] have found that beyond certain timescales the time dynamics of
both plane and car accidents are not Poissonian but instead long-range
correlated._ [2]

[1][http://arxiv.org/abs/physics/0509092](http://arxiv.org/abs/physics/0509092)

[2][http://arxiv.org/abs/0901.3183](http://arxiv.org/abs/0901.3183)

[3][http://www.sciencedirect.com/science/article/pii/S0378437107...](http://www.sciencedirect.com/science/article/pii/S0378437107003111)

------
mikeash
I feel it's important to point out that this is _not_ a cluster of three
airliner accidents. It's a cluster of two accidents and one crash due to
military action. While they presumably didn't intend to shoot down an
airliner, the only accidental part was that they killed different people from
who they wanted to kill.

I don't think this affects the probability discussion much, but it's good to
call it what it is.

~~~
scholia
Or possibly one accident. We don't know what happened to MH370....

~~~
mikeash
MH370 is not among the three being discussed.

~~~
scholia
Ah, sorry...

------
philh
> In fact, Ranter says it is more common for an accident to happen just one
> day after another crash than two, three or more days later.

As written, a poisson distribution wouldn't explain this. If you have a crash
on day 0, then a crash on day 1 is no more likely than a crash on days 2, 3,
etc.

Day 1 is the day most likely to have the _next_ crash, but it's no more likely
to have _any_ crash.

(It could easily be the case that Ranter actually found "...just one day after
_the previous_ crash than two, three or more days later", and this subtlety
got lost somewhere down the line.)

------
low_key
I don't agree with the term 'accident' for crashes because they can always be
attributed to causes, not just chance.

This is even more true when missiles are involved.

~~~
drzaiusapelord
Its concerning how the Pro-Russian narrative has been formed over the shooting
down of that plane. We don't call the shooting down of planes during the Cold
War accidents, but somehow we do for this?

The world is coddling Putin for fear of losing his economic ties into
countries that control the editorial content of much of the Western press. So
we say 'accident' and we say 'supposed' ties to Russia, and we say blatant
lies like 'Nazi party has taken over the Ukraine' in Western papers.

Sadly, Putin's money is held above morals and truth in Europe. Especially in
Germany and France.

~~~
arjie
For reference, the downing of Iran Air Flight 655 was termed in the US
report[1] as a "a tragic and regrettable accident". The report goes on to use
the word 'accident' many more times.

[1]:
[http://www.dod.mil/pubs/foi/International_security_affairs/o...](http://www.dod.mil/pubs/foi/International_security_affairs/other/172.pdf)

------
Coincoin
Yesterday in Toronto, a plane made an emergency landing. The news ignored it
as just an usual everyday thing, because you know, it happens everyday... Just
kidding, they actually called it a "multiplication" of aviation incidents.

------
platz
"But the chance the next crash is on 3 August is (364/365) x (1/365), because
the next crash occurs on 3 August only if there is no crash on 2 August."

Why is a crash on 3 August dependent on there being no crash on 2 August?
Surely there could be crashes on both 2 August and 3 August.

~~~
shawabawa3
Because if there was a crash on the 2nd and the 3rd, the one on the 3rd
wouldn't be the _next_ crash.

------
clueless123
People pay more attention to airplane accidents right after a large accident
event.. Google plane accidents and you will see that they happen all the time,
they just don't get the world wide news coverage.

~~~
scholia
News is a fashion industry. One big "dog mauls child" story will be followed
by other "dog mauls child" stories that would otherwise not have been
reported. The difference is that they are "news" now when they weren't news
before....

~~~
easyfrag
Yep, summer 2001 was the "Summer of the Shark Attacks" because of a couple of
high-profile incidences. The news media played it up as some sort of epidemic
although there was no significant difference in the numbers. This went on
until September when a bigger story came long.

------
lifeisstillgood
My question is how far has decades of cut throat competition eroded the safety
and maintenance standards of all airlines?

Minimum standards are high - and well respected. But if you shave off costs -
even if each one is trivial - put back investment, dial back on the training,
will I have a cumulative effect?

In short, when will air travel trend towards rail and road for accidents ?

~~~
WalterBright
> My question is how far has decades of cut throat competition eroded the
> safety and maintenance standards of all airlines?

It hasn't. They're safer than ever.

But keep in mind that while airliners are very robust against all kinds of
mechanical failures, human errors, and natural events, they are not designed
to withstand battle damage or to have any sort of countermeasures. Their only
safety from attack is they fly at high altitude, out of range of small arms.

------
calinet6
This is absolutely correct and insightful. Glad to see it on the BBC.

Now here's a scary question: when you want to give someone a bonus because of
their successful performance over the last 6 months, how likely is it that
their string success is a coincidence?

You're forced to make a similar conclusion, and if you don't, think about why
you have the bias you do.

~~~
yaks_hairbrush
That's not a scary question. One could simultaneously believe that an
employee's performance was coincidence, but still give that employee a bonus
(why not reward luck, after all?).

~~~
calinet6
You don't reward luck because the negative effects of individual bonuses on
the entire workforce cause more harm.

You recognize the truth: that your whole team is responsible for working
together to solve the problems of the company, which are necessarily complex
and large (otherwise, you'd only need one person) and individual salaries are
based on their baseline skills and abilities in that context.

Visible public reward of individuals for work that's perceived (and truly
required) to be a team effort is visibly detrimental.

------
spacefight
All crashes as mentioned:

\- MH 17 [http://www.aeroinside.com/item/4365/malaysia-b772-near-
donet...](http://www.aeroinside.com/item/4365/malaysia-b772-near-donetsk-on-
jul-17th-2014-aircraft-was-shot-down)

\- Transasia in Taiwan [http://www.aeroinside.com/item/4389/transasia-at72-at-
makung...](http://www.aeroinside.com/item/4389/transasia-at72-at-makung-on-
jul-23rd-2014-impacted-buildings-on-approach)

\- Swiftair MD 83 in Africa [http://www.aeroinside.com/item/4393/swiftair-
md83-over-mali-...](http://www.aeroinside.com/item/4393/swiftair-md83-over-
mali-on-jul-24th-2014-aircraft-lost-altitude)

------
ermintrude
I read a book once - I think it was the Gift of Fear (but I might be wrong) -
that said that plane crashes often occur in clusters, same with other
tragedies like mass shootings at schools etc. The author suggested this was
because people who might do those things - or in the case of pilots, pilots
who might want to commit suicide and take the plane down with them - get
prompted to act when they see other incidents have occurred. So according to
that author, these events are not random.

Obviously a civilian plane being shot down would lie outside this theory (he
suggested more plane crashes were due to pilot depression than mechanical
fault/other factors).

~~~
lotsofmangos
If these events were completely random, then we would expect them to happen in
clusters. Randomness is pretty clumpy.

~~~
lilsunnybee
Actual correlations can be pretty clumpy too. Definitely have to look at the
overall distribution.

------
billmalarky
"the most likely maximum number of crashes of commercial planes with over 18
passengers in any eight-day window over 10 years is exactly three".

So if another crash occurs are we allowed start the conspiracy theories?

~~~
karlkatzke
Only if there were no surface-to-air missiles involved.

~~~
meowface
I think some group shooting down planes with surface-to-air missiles would
constitute the definition of some sort of a conspiracy. Just not a very subtle
one.

------
bitL
Time between disasters has exponential distribution (or the number of
disasters in given time adheres to Poisson distribution). Something we were
taught at the university.

------
jdcryans
For those interested, a good source for a lot of publicly reported crashes,
accidents, incidents and whatnot is The Aviation Herald. Here's the list of
all their recorded crashes sorted by occurence date (toggle the icons next to
"Filter" to see more kinds of events):
[http://avherald.com/h?list=&opt=7681](http://avherald.com/h?list=&opt=7681)

------
tpeng
The Werther effect could be another explanation for clusters of airplane
crashes:

[https://fc.deltasd.bc.ca/~dmatthews/FOV2-00074762/S02DB0598....](https://fc.deltasd.bc.ca/~dmatthews/FOV2-00074762/S02DB0598.2/Cialdini%20airplane%20studies.pdf)

------
ackfoo
While it is impossible to reduce chaotic systems to individual factors, and it
is likewise impossible to predict the effect of an individual factor upon the
system as a whole, it is certainly possible for one factor with a global
effect to move the entire system towards or away from a probable outcome.

If we postulate that, now absent the selection pressures that have shaped
human intelligence over the last few million years or so, human intelligence
is likely to decline, then we can ask ourselves where this decline might be
likely to first show up in the chaotic system of human endeavour.

One possible answer is that it will appear first at the boundary layers: the
places where a critical level of human intelligence is required to keep a
complicated task operating.

I propose that flying passenger aircraft is such a task. A critical level of
intelligence must be maintained by a very large number of people in order to
keep passenger aircraft in the air. Everyone, from designers to manufacturers,
to QC, to maintenance to pilots to airline management has to function above a
certain critical level to perpetuate the activity.

It is possible that clusters of aircraft accidents are purely random and part
of the complex system that is air travel. However, it is possible that
clusters of aviation accidents represent crossings of the boundary layer
resulting from the change in a global factor, like human intelligence, that
has moved the entire system probabilistically.

The details of some recent accidents should give us pause. The series of over-
control/mis-control accidents including AF447, Colgan Air and others defy
reasonable explanation, and they appear to have no precedent in recent
passenger aviation. MH370 and MH17, so far as we can see, have no reasonable
explanation other than unaccountable human behaviour (failing to communicate
over the course of seven hours flying in the case of MH370, and navigating
over a war zone in the case of MH17).

It is possible, although certainly not provable at this point, that we are
simply becoming too stupid (in general) to fly passenger aircraft safely. It
may be time to switch to fully automated aircraft systems.

~~~
lifeisstillgood
Sadly if humans are too stupid to fly them, we are certainly too stupid to
tell a computer how.

~~~
robotresearcher
That's not true at all. The computers can do control corrections much faster
than humans. A human could not fly a quadrotor drone by controlling the
current to the individual motors: computers fly them just fine. Very often we
know how to control things but humans can't do the computation fast enough.

