[lucasjung]

He's still wrong: human error is a factor in the overwhelming majority of aviation mishaps (I don't have stats handy, but it's something in the neighborhood of 85% IIRC).

This must be understood in the context that while it is almost always a factor, it is rarely the only factor. Aviation mishaps typically occur when three or more factors combine. For example, if you're just low on gas, or just in bad weather, or just a little bit tired, you probably won't have a mishap, but put all three together and things can rapidly get out of hand. In the case of AF 447, they were in bad weather (which caused a malfunction in the FCS), they had CRM problems (Captain was not in the cockpit, and the two pilots who were in the cockpit did not coordinate well), there were serious flaws in the HMI design (the most egregious example, in my mind, being the averaging of the stick inputs), and the crew was not sufficiently trained on how to respond to FCS failures.