Why 'Plan B' often works out badly[ Fri, 18 Mar 2011 01:16:06 GMT ]Engineers used to talk about guarding against the “single point of failure” when designing critical systems like aircraft control networks or nuclear power plants. But rarely does one mistake or event cause a catastrophe. As we’ve seen in Japan, disaster is usually as function of multiple mistakes and a string of bad luck, often called an “event cascade” or “propagating failures.”