This is wrong. And that's because safety deals with probabilities, not absolutes. In the absence of absolutes, people who are also responding to contrary pressu

This is wrong. And that's because safety deals with probabilities, not absolutes. In the absence of absolutes, people who are also responding to contrary pressures (time, money, etc.) can find themselves shifting the lines between likely, unlikely, highly unlikely, and statistically impossible. This is especially true when dealing with complex systems that defy attempts to model interacting forces perfectly. [EDIT] The 787 is conspicuously (and very expensively) behind schedule. It also represents an especially large investment of ego on the part of senior management, who were basically at war with their unions, and developed the globally distributed production line for the 787 in response to their conflicts with workers in Seattle. This included the construction of a fleet of supersized jets that could move fuselage size parts-in-progress around the world, meaning parts of the 787 assembly line are, quite literally, airborne. In other words, Boeing is no longer operating in the realm of tried-and-true. To the contrary, they're pushing aircraft manufacturing into uncharted territory. The premise that this was an intelligent response to labor issues has already come under serious fire, in that the distributed assembly line has been credited with an inordinate number of the delays they're suffering from (relying on sub-contracted manufacturers in Italy, for instance, proved especially costly). So there's already a bit of a siege mentality happening at the highest levels of Boeing HQ, and a lot of pressure to pull off what is, in retrospect, looking like a major miscalculation. Put simply, if they were going to err on the side of caution, they wouldn't have pioneered outsourcing on this scale using their flagship product in the first place. When the "appetite for risk" comes from the top down, it's much harder for subordinates to draw the right lines.