331's biggest drama is on start, get that prestart temp down and give it just enough juice and they're fine. Only problems overall that I've seen was gens, NTS etc. Operationally the engines just keep going.
Now I know you don't fly 'em.
Pre start temp does not effect them very often at all unless you have crappy battery's. Give the prop 30 blades after shutdown. disembark, chuck the bags 'n load her up, hit the starter test and at 15% hit the start button, away she goes.
You will never know you have a NTS failure until the engine stops even after successful NTS checks on first taxi every morning
Or you do a shutdown in flight for training purposes, use the unfeather pump to unfeather the propeller and she starts disking on you without NTSing while you are attempting a start. You'll run out of rudder before you worked out what happened............
BTW how do you give it just enough juice? The SRL computer maintains about 690-710 on start, you can add a bit to get it there quicker if it's bogging down around 40% but not as a rule. (you can tell me how you do this if you like)