Originally Posted by
TiredSoul
I don’t know anything about those engines, prop governor and backup or fail safe systems.
Any chance an outboard prop going flat or even beta could have caused this?
It's possible. There are systems in the prop intended to prevent a prop going into flat pitch in flight, but like anything, they're not infallible. I know of at least one instance where a prop has gone below the low-pitch stop in flight.