The holy grail of the 5 Nines

In 2011 there were 18 passenger flights worldwide that resulted in fatalities. In that year, the US alone had 10 million flights. If 99% of flights in the US were safe (meaning 1% of flights resulted in fatalities), there would be an alarming 100,000 flights with fatalities in the US each year. 

99.99% safety would still be a frightening 1000 flights with fatalities each year.

Incredibly, that means that even if all 18 of the passenger flights with fatalities in 2011 had been in the US, the safety rate for US flights that year would have been greater than 99.9998% The fact that none of those passenger airline flight fatalities occurred in the US means the actual safety rate for that year is even greater. Andy Chen, Quora

Our Internet connection has been down 33 minutes since the beginning of the school year - out of a total of 231,830 minutes in the past 23 weeks. That give us a downtime of about .014% or 99.986% uptime.  (According to the numbers above, we would have lost only about 150 planes last year.)

Ten years or so ago our local telephone company took a bunch of tech folks to a big seminar in Minneapolis to help us learn about VOIP (Voice over Internet protocol) - the then newish technology that allowed delivering telephone services over our computer network instead of dedicated analog lines.

At the time, the telcos were heavily invested in traditional telephone service so the big takeaway from that meeting was that the only technology in operation that met the 5 Nines criteria - that it works 99.999% of the time -  was, you guessed it, the analog telephone system.

A concern was raised recently about whether building emergency plans should rely on e-mail as a means of communicating to those in buildings about a possible threat or emergency. "What if the Internet goes down?" was the gist of the worry.

While nothing is certain and a technology-free backup plan is a good thing, I am not sure just how much time I'd spend worrying about a failure rate of .014% - especially when you multiply that times the 1 in 1 million odds of a student being killed in a school shooting.

I am an English, not a math, major so my numbers may be off. But I'll bet the farm that spending time working on building emergency plans that circumvent modern communication methods is time that could be better spent. On nearly anything.