The vocabulary in this field has grown faster than the ideas. Half a dozen named types circulate, several of them describing the same behaviour from different angles, and a site can waste real time deciding which one it is doing. What follows is what each term means and, more usefully, which assets each is the correct answer for.
Corrective and run to failure: fixing what broke
Corrective maintenance is work done to restore an asset after a fault has been found, whether the asset stopped or an inspection caught it first. Run to failure maintenance is the deliberate decision to wait for the stoppage, and it is a legitimate strategy for cheap, redundant, quickly replaced assets with no safety consequence. The distinction that matters is intent: corrective work following a planned inspection is a programme working, while corrective work on an asset nobody had thought about is a programme with a gap.
Planned preventative maintenance and ppm
Planned preventative maintenance, usually shortened to ppm maintenance, is the interval-based work that makes up most of a normal programme, and the abbreviation is common enough in British usage that the full phrase is rarely written out. Preemptive maintenance is used loosely to mean the same thing, sometimes with an implication of acting on early warning. None of these are technically distinct enough to justify choosing between them; they describe scheduling work before failure rather than after.
Autonomous and risk based: who does it and why
What is autonomous maintenance: the practice of operators performing basic care of their own equipment, cleaning, inspecting, lubricating and reporting, rather than waiting for a maintenance visit. It works because the operator is there every day and notices change first. Risk based maintenance allocates effort by consequence and likelihood rather than uniformly, which is what any sensible programme does implicitly and this names explicitly. What is deferred maintenance sits opposite both: work identified, postponed, and still owed.
Questions people ask about corrective maintenance
What is corrective maintenance?
Work to restore an asset after a fault has been found, whether it stopped or an inspection caught it. Corrective work following a planned inspection is a programme working, not failing.
What is autonomous maintenance?
Operators performing basic care of their own equipment: cleaning, inspecting, lubricating and reporting. It works because the operator is present daily and notices change first.
Is run to failure ever the right choice?
Yes, for cheap, redundant, quickly replaced assets with no safety consequence. The failure is running to failure by accident on something whose stoppage costs a shift.