RTFI
you are probably right about engine failure statistics being misunderstood. There is a consulting engineering company based in Guildford who specialise in risk analysis. They spend a lot of time explaining to people that a 1 in 10 000 000 hour event has nothing to do with when an event will occurr or on the likelyhood of it happening tomorrow. In fact they can do some very interresting risk calculations that build in the real life factors that can give some very different and vey un-nerving answers.
As a general rule of low risk of occurance with high consequences if it does requires a very high 1in x figure to be quoted. I am not sure 1 in 10 000 000 as you quote is particularly reassuring or that it actually means anything!
