Human Unpredictability: The Fact No One Likes to Admit

http://www.cnn.com/2015/03/30/europe/france-germanwings-plane-crash-main/
Here we see yet another airliner tragedy, caused by at this time what is assumed to be a suicidal pilot who purposely grounded the plane. 150 people were killed, including the co-pilot who had commandeered control of the plane from the pilot while he was on a restroom break, using the very safely system installed in planes to prevent such tragedies from occurring in the first place.
Following this tragedy was social and political uproar, and rightly so. Something like this should not be taken lightly.
Again that so-often asked question is being asked, "How could we prevent this in the future, so that this would never happen again?"
Therein lies the problem. While the crash was a tragedy, it was only possible because of one thing-- human unpredictability-- a concept that we seem to have trouble grasping in this age of science statistics and psychology. You can't put human behavior into a math equation.
The article states that the copilot Andreas Lubitz had indeed experienced extreme depression and even suicidal thoughts before he trained for his pilot's license, but had [apparently] overcome those thoughts since then, Perhaps this was true. Perhaps when Lubitz underwent his exam, he was perfectly fine: the epitome of human healthiness. Later perhaps the depression again descended upon him, undetected by everyone he knew. Perhaps the thoughts remained with him the entire time, concealed behind a carefully crafted mask. Perhaps he had ulterior motives outside his own demise. We very well may never know, despite what most people seem to be saying.
I particularly find it interesting, (and fairly ironic) that the very system that had been built to ensure passenger's safely on the plane was the method of destruction in this particular accident.
Where am I going with this? All I mean to say is this: that any system, no matter what it concerns, as long as it is human-made, will be flawed. Why? Because we are flawed. Can we learn from our mistakes? Yes, and indeed we must. That's how we have gotten this far. But even now, today with all its marvels and accomplishments, we still experience glitches in the system, and we always will.