Originally Posted by
suninmyeyes
The oil filter bypass opens when the pressure in the oil filter increases past a certain psi. I have had it due to metal particles in the filter and the checklist has you retard the thrust lever until the message disappears, if it does not disappear the engine has to be shutdown. The emergency would have been declared as the aircraft could not maintain its assigned flight level on one engine and would need to descend. However I would not call the subsequent landing an emergency landing. To me an emergency landing is when there is difficulty with the aircraft handling or some doubt the aircraft can be landed safely and stopped on the runway without risk to passengers. One engine running at idle is hardly an emergency landing.
The following refers to the technical aspects of filter blocking; SOP's may say something entirely different.
I'm not saying that you are wrong in this case, but most filter blocking indicators that I have run into do not just detect absolute pressure but use a differential pressure switch ( or two pressure switches) to detect when filter blocking is about to become a problem. It will, of course, continue to alarm if the situation deteriorates.
But the intention is to alarm before unfiltered oil start streaming through the bypass relief valve.
If by reducing engine speed you can reduce the differential pressure across the filter then you should be safe provided that the by-pass did not open while the alarm was active.
And you don't really know whether that happened or not.