Interesting documentary on SBS about the Germanwings tragedy, if you want a deeper insight see my post on the dirty little secret of civilian aviation. By the way, the two person rule only works if both those people are alive.
With a Bachelor’s in Mechanical Engineering and a Master’s in Systems Engineering, Matthew Squair is a principal consultant with Jacobs Australia. His professional practice is the assurance of safety, software and cyber-security, and he writes, teaches and consults on these subjects. He can be contacted at firstname.lastname@example.org