why do we call maintenance problem deviation? Deviation from what?

Question

The nature and definition of problem analysis and decsion making.

Answer 1

Well, if its standard preventive maintenance or better yet predictive preventive maintenance it is really not a problem but a necessity and therefore it is scheduled and within the standard work process.

Unscheduled maintenance or sporadic downtime because of maintenance is a "deviation" from the standard work process or process flow. It has a cause and it has an effect and it can be controlled. When something goes out of control it deviates from the norm or the standard.

That's my version.