Is the advice to operate as much as possible at “cruise” rpm (96ish percent) new? And by new I mean like this century, since the Honeywell takeover.
When I first started flying 331 powered planes it seemed like the mantra was “sure, you can pull it back a few percent - if you can’t handle the noise, and like going slower. But the engine was designed to run at 100% and it is most efficient at that rpm.”
I actually got a call from chief pilot for reducing rpm on short flights that only justified a climb to 16.5/17.5.
I never heard about any problems with 100% until about 10-15 yrs back at recurrent, there was a Honeywell handout (I still have it somewhere if anyone needs it) that said basically the opposite.
What I thought they left out was actual objective data. Like how much wear, hot section expense etc. I wish there was some data along the lines of “If you run the engine 3% slower and 30 degrees hotter you’ll lose 10 percent of your climb and 3 percent of your cruise, but save $100,00 in T blades over the life of the engine.