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To fly or not to fly—hard choices with ash

A few months ago there was a huge stop in European flights because of volcanic ash from Iceland. Some airline companies, like Lufthansa, became impatient, conducted their own experiments, and found (or at least claimed) that flying is safe. Officials claimed otherwise.

Anyone understands that airline companies have high financial pressures to fly. Being idle is terribly expensive, and will soon lead to bankrupt. But most people would like to think that airline companies wouldn’t risk peoples’ lives, not at all. They would make it 100 % certain that if they fly, the planes are not at risk. After all, an accident would be not only a human catastrophe, it would also be a catastrophe for the company, business- and reputation-wise.

But making business is about making choices and taking risks. Choices are made by assigning costs to alternatives, and estimating probabilities to their outcomes.

Probabilities are finite. There’s no such thing as 100 % safety with anything, including flying. The only certain way to avoid flying accidents is to not fly. We may be talking about 99.99 % or 99.999 % safety, but not 100 %.

Sometimes hard choices must be made—hard in the sense that the result of either choice’s risk getting realized is catastrophe. Let’s assume 1 that a company estimates that if they start flying now instead of after a month (when the ash has gone away), there’s a 10 % risk that one plane will crash during the month because of the ash. Let’s also assume that if they don’t fly during that month, they’re bankrupt with 90 % probability (I don’t know how long a company can stay idle; nobody knows how long the ash stays in the atmosphere; adjust the timeline as appropriate). That is, a choice:

  • Fly. There’s a 90 % probability that all goes fine.
  • Don’t fly. There’s a 90 % probability that the company goes bankrupt.

Which one does a business company choose?


  1. These “either/or” choices are of course gross simplifications. The companies could choose to fly at an “ashless” altitude which increases fuel costs but reduces risks, or fly at certain routes only. A plane could get badly damaged (which is expensive and scary) without crashing. There are lots of in-between alternatives. Nevertheless, the major point in this thought experiment remains valid. 

Last modified: 2010-08-07 11:26 +0300


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