> Would you feel comfortable using the processes you have used in the past to develop a system where compromise would result in the loss of human life?

I don't think that's a fair question. Life-or-death software systems (such as avionics) are built using very different methodologies than ordinary software, and their development costs (and times) are orders of magnitude higher. If ordinary software were held to the same standard, almost no software development projects would pay for themselves.