[kryogen1c]

To quote from a paper I read and love but cannot find, Meditations and Reflections of a Naval Reactors Engineer (i would pay money for):

Because everyone cares deeply about about their jobs, mistakes tend to be either extremely subtle or extremely glaring.

Normalization of deviance leads to the latter, although for different reasons. It is to prevent things like this that the nuclear navy forces people to rotate commands every few years.