I never heard but I guessed that a stuck prop feathering relay is what caused the Dutch Dakota crash a few years ago. Can anyone confirm that?
The feather check isn't that complicated, push the button, the RPM goes down, look at the load meters, pull the button back, the RPM comes back up, look at the load meters. You do want to give the button a twist before you start because I have seen the little button come off the threaded rod behind it when it was pulled back out.