Hmmmmm.
I would be surprised if the TR worked at that RRPM.
BTW. Check the RFM for MIN RRPM Power On.
Underspeed probably just as bad as an overspeed.
Get back to us with the Reg No. and Serial No. of the airframe so we can get the barge poles out.
You did this “intentionally” right? And just what was the point?
Better still as it was an exceedance of the limitations let us know what the AMM has to say and if there is no procedure for inspection, send the details to the manufacturer and let us all know what they have to say!
Looks like “there is one born every day” still rings true.