Having flown 217 across both the Atlantic and the Pacific, I might not be the right one to ask......or I am. Scotland to Norway.....Nome to Kyoto, St Johns to Azores, Goose to Reykjavik and California to Hilo Hawaii, the longest overwater stretch you can find.
It can happen at any time on any engine, but the statistics have convinced EASA that AOC, single-engine turboprop is now permitted. So......I don't want you to lose sleep, so not a word about the single-engine pistons! ;-)