MH17 MH370 pair probability v single v conditional v unconditional

July 26, 2014

How should we think about the MH17 and MH370 events in probability terms?

One way is we take the MH370 as given. We also take the shoot down in Eastern Ukraine as given. We then ask what is the chance that the plane model will match. We simply count the number of times that model crosses Eastern Ukraine in some reference time, e.g. each day, and divide by the total number crossing. That could be total number of commercial planes or some other set.

We can also require the plane match on airline and model. So we take the Malaysian 777 and the same model and divide by number of commercial crossings, if that is our choice as comparison.

We could at this point, also look across all war zones and ask what is the chance that in any war zone, the model matches to 777. Or that it matches to Malaysian Airlines and the model 777.

We might also think about the issue of probability per unit time and the time unit we should use to aggregate.

We can also do a sort of reverse conditional probability.

We can take as given that it was a Malaysian 777 that went down in Eastern Ukraine. We then ask what is the chance that the plane that disappeared would match on the model and airline? So we take every commercial airplane in the world, say it is 100,000. Then count the number of Malaysian 777’s, say 10. So we have 10/100,000 or 1/10,000.

We could also ask what is the chance that some commercial flight crossing Eastern Ukraine would match to such a disappearing plane, now randomizing over both. So we are asking a pair probability.

For each flight crossing Eastern Ukraine, we then compute the chance it would match another plane disappearing of that airline.

We could also require that the destination airport match. MH17 was headed to Kuala Lumpur the same airport that MH370 flew out of. We can require that match in our probability question.

We could also expand to include all war zones in the world not just Eastern Ukraine. We could also consider over time. Why has this never happened before? Presumably, however we do the probability, the pair probability is low for this type of matching of the model and the airline and airport.

As we think in these terms, it seems the chance that the Russians didn’t plan both planes together before either plane went down is lower.

Some ideas on number of Boeing aircraft from following article.

Number United Airlines.

The location of Kuala Lumpur seems special. It is a destination of a flight from Europe over Eastern Ukraine and it is ideal for an aircraft to disappear into the oceans. It would seem few airports match such a pairing.

It seems more like this pair of aircraft were chosen by Russia from the beginning before either event happened.

This is draft and preliminary. The above is hypotheses and speculation. Comments and corrections welcome. Please restate as questions. All other disclaimers apply.


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