Just a couple more comments on the TPE331
I flew the Metro III (SA227) for 3000 hours.
NTS operation also includes *automatic* (on the SA227) ignition to aid in the re-light.
The point is, in case of ice/water ingestion, there might be a momentary loss of power. In the meantime, the prop moves *towards* feather to reduce drag while the ignition comes on to help the re-light when the ice/water is finally clear. It all happens very quickly and in 3000 hours of flying around Alaska I only saw it happen once.
The Garrett is quite durable and the engine inlets have sufficient heat but the SPINNERS have no ice protection whatsoever. You really need to be very cognizant of those chunks of ice and what happens to them when they depart the spinner.
I would run the ignition *constantly* until the ice on the spinner finally melted off.