Every time I think I have seen the ultimate in pedantry, pprune manages to raise the bar
. I would suggest when the engine ceases to provide thrust you have suffered an
Engine Failure. Whether the reason it has suddenly got quiet was because the crankshaft broke or you let sufficient carb ice develop that the engine could not run makes not a whit of difference to that fact.
What is different is that there
may not have been any warning of the crankshaft failure but there
would absolutely be warning that carb ice was developing.
However even catastrophic internal failures often give some warning in the form of sudden increases in oil consumption, abnormal temps and pressures, or unusual sounds/noises. The only serious engine problem I have ever had in a single was a failing oil pump drive in a C 150. I caught the declining oil pressure early and was able to get to within gliding distance of my home airport before the oil pressure went to zero and I shut the engine down. Since I shut the engine down and got on the ground before it failed the authorities did not count it as an engine failure.
Now if I had not paid any attention to the gauges and let the engine run on no oil pressure until it inevitably failed then I would consider this "engine failure"
as falling into one of the 80% that where pilot action/inaction contributed to the failure.
Rod 1: What engines did you have your failure and partial failure ?