The Anatomy of an Outage
An outage is never a single event; it is a chain that was allowed to complete. Somewhere upstream a component failed, and at every step after that a barrier that should have stopped the failure was missing, degraded, or mis-wired. The trained reader does not ask what broke. That is the least interesting question, because everything breaks eventually. The reader asks why the break was permitted to travel all the way to the customer. Learn to see the chain and the empty slots where barriers belonged, and an outage stops being bad luck. It becomes a legible record of the choices an operator made about where to spend money and where to gamble.
Knowledge check
In fault-tree terms, what distinguishes the root cause of an outage from the reason the outage reached customers?
Show the answer
The root cause is the initiating component failure, which is common and expected; the reason it reached customers is the sequence of redundancy barriers that failed to contain it. Reading an outage means tracing both, because the missing barriers reveal the operator's real design and discipline far more than the trigger does.