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How odd is a cluster of plane accidents?

155 points| arb99 | 11 years ago |bbc.com | reply

83 comments

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[+] gleenn|11 years ago|reply
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|11 years ago|reply
"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.

[+] 31reasons|11 years ago|reply
One thing that really surprised me is that how laid back the attitude was of commercial airliners about the Ukraine war zone. It was already in the news that they are shooting down the war planes. So basically they were betting on some Russian missile system that would identify war plane from commercial planes. I would cancel all flights from a region thats engaged in any form of airborne projectiles.
[+] jameshart|11 years ago|reply
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.
[+] drzaiusapelord|11 years ago|reply
This is such a good point. Sometimes I have to explain to people that coincidences aren't weird. It would be weird if there no coincidences.

But that usually detracts from some of their spiritual/political beliefs and its quickly dismissed.

[+] Someone|11 years ago|reply
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.

[+] mxfh|11 years ago|reply
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

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

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

[+] mikeash|11 years ago|reply
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|11 years ago|reply
Or possibly one accident. We don't know what happened to MH370....
[+] philh|11 years ago|reply
> 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.)

[+] unknown|11 years ago|reply

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[+] low_key|11 years ago|reply
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.

[+] kazinator|11 years ago|reply
Indeed, even if a missile strike is accidental in the sense of mistaken identity, it is misleading to call the situation a "plane accident" or "air traffic accident". It is a military accident.

Just like when a car is blown up by driving over a mine, we don't call that a "car accident" or "traffic accident".

Doh?

[+] squeaky-clean|11 years ago|reply
I think it is silly to argue such semantics with natural language. We all know what it means when they said "accident." Something unintentional, unexpected, and unfortunate. So why do we need to go off topic and argue whether something was the correct word, when everyone is aware of the meaning implied. In this context, "crash" and "accident" are really the same. The events are random and out of control from the perspective of the airline or passengers, the people who matter in this post.

It's not like we're programming, where (hopefully) 2 != two != "two" != "2"

[+] drzaiusapelord|11 years ago|reply
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.

[+] duaneb|11 years ago|reply
Accident just means unintended. And while there are causes, they may now well be unknowable, in which case a statistical look is probably the most interesting look you can justifiably make.
[+] zorbo|11 years ago|reply
Someone driving in a car who's not paying attention for a moment and hits someone else feels like an accident to me. The same could have happened with a missile. Strictly speaking, everything has a cause. So by that definition there are no accidents.

That's all just arguing semantics though. I even agree with you that the term "accident" is not correct, despite what I wrote above. (Although I don't agree with your reasoning behind it). I'd prefer the term "incident".

[+] frobozz|11 years ago|reply
An event doesn't have to be purely random (whatever that means) to be an accident.

An accident is something that happens unintentionally. Though I'm sure many crashes are down to genuine negligence, I'd be surprised if most crashes are deliberate, even indirectly (e.g. "Whoops! I've cross-threaded this bolt, oh well, I'm sure it will be fine" vs "Ha Ha! I'll cross-threaded this bolt. That'll make the plane crash one day!").

[+] shangxiao|11 years ago|reply
'accident' doesn't mean that the crash happened by chance, just that it was unintentional.
[+] Qantourisc|11 years ago|reply
Imo accident is an "oeps" that occurred without intend. In case of a fired missiles it's an incident. So unless someone misfired the missile it's I'd call it an incident.
[+] IvyMike|11 years ago|reply
When do you use the word 'accident'?
[+] vaadu|11 years ago|reply
The outcome of the shootdown was easily foreseeable given the circumstances, so I don't see how it can be described as an accident.
[+] Coincoin|11 years ago|reply
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|11 years ago|reply
"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|11 years ago|reply
Because if there was a crash on the 2nd and the 3rd, the one on the 3rd wouldn't be the next crash.
[+] UrlichtZwei|11 years ago|reply
The Aug 3 crash can't be the "next" crash if the "next" crash occurred on Aug 2.
[+] clueless123|11 years ago|reply
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.
[+] notahacker|11 years ago|reply
Aircraft accidents are common; commercial airline accidents, especially those apparently happening in mid-air are very rare. Even thirty year old trijets operated in Africa crash infrequently enough to warrant global news coverage, albeit not news coverage that many people pay much attention to or that the BBC sees fit to create a live update page for.

What's actually a far bigger coincidence is that there were no fatal 777 crashes in the first 20 years of a >1200 aircraft production run until this year, when two aircraft belonging to the same airline were both total losses in apparently unrelated cases of apparent foul play. Whilst I can't conceive any conspiracy theory linking the two that would be credible even by the low standards of the average conspiracy theory, that's a far bigger statistical anomaly.

[+] scholia|11 years ago|reply
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....
[+] lifeisstillgood|11 years ago|reply
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|11 years ago|reply
> 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|11 years ago|reply
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|11 years ago|reply
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?).
[+] ermintrude|11 years ago|reply
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|11 years ago|reply
If these events were completely random, then we would expect them to happen in clusters. Randomness is pretty clumpy.
[+] sazpaz|11 years ago|reply
Robert Cialdini also brings the same theory in his book Influence. Not only that a tragedy prompts other to the same action, but he showed some studies where a type of tragedy prompted a seemingly irrelevant event.

For example, 2 days after a suicide appearing on the news, it is significantly (don't remember the exact numbers) more likely for there to be a plane crash. He attributes this to the fact that some pilots that have had suicidal thoughts are triggered by the suicidal news.

Another interesting study looked at how mortality rates of car accidents are higher after suicide-related news. This study found a surprising number of car deaths in which the driver was stepping on the gas pedal, instead of the break, which might be an indicator of suicide.

[+] michaelmcmillan|11 years ago|reply
I don't think mass shootings can be considered to be random events, although they probably occur in clusters - I think that's due to the extensive media coverage.

"Why does a psychiatric expert on these phenomena personally advise mainstream media outlets about how to handle these situations - and they do exactly the opposite time and again?" [1]

[1] https://www.youtube.com/watch?v=Stc42j4Nz2w

[+] billmalarky|11 years ago|reply
"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|11 years ago|reply
Only if there were no surface-to-air missiles involved.
[+] bitL|11 years ago|reply
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|11 years ago|reply
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
[+] unknown|11 years ago|reply

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