"
What are the circumstances that will require the entire A320 static inverter to be replaced?"
When the
elapsed time counter inside the inverter shows it needs to be replaced.......ahem !
The time counter may come as a surprise to many on here....as indeed it did to me at the time...as I will explain. A few years ago, I was involved in a little project concerning cost savings for one particular type ( not Airbus ) ....after a decidely protracted process, eventually, strip reports were produced by the organisation concerned ( I was not directly employed by them, thankfully ! ) and the little gem above appeared.
The scam was very simple....the report was written in such a manner that, to a non engineering person, it was
very plausible...and therein lay the catch....if the costs associated with the overhaul of components were below £xxx then they were simply signed off by an admin clerk....no engineer ever read them....thus, it took little or no effort to write a report which looked convincing to justify the, ahem, "extra costs" involved...several more reports for different components from different repair / overhaul organisations showed the same scam.... a short time later....the project was, erm, suddenly cancelled.
The scam must have been going on for years with insider knowledge....until an engineer read the reports that is.
The plus side was that, a couple of years later, the organisation had a "restructuring exercise"...karma, as they say, duly arrived.