Ice protection...

Ice can form under the inlet screen, on intake lip or any piece of solid material subjected to the airflow when precipitation and subfreezing temperatures exist. As I mentioned above, the engine itself does not integrate an air induction anti-icing mechanism, but the King Air airframe does. As we all know, the engine anti-ice vanes should be deployed in temperatures of +5 degrees to +10 degrees Celsius and below when operating in visible moisture. However, the use of this anti-ice mechanism cannot protect the engine from damage if the buildup is downstream of the ice vanes. This build up can break away and be ingested by the engine while descending from freezing altitudes into warmer temperatures. In 1982, P&W circulated a Field Note to PT-6 operators describing how ice buildup under the inlet screen can break off and be ingested causing first stage compressor blade damage, usually in the form of a single bent blade. They also emphasized the importance of deploying the ice vanes before entering icing conditions. King Air Nation

[...] The key to eliminating this problem is to extend the ice vanes at +5º C when in visible moisture. If its night and you can’t tell if visible moisture is present, extend them anyway!

Of course, FOD isn’t only ice induced.
The following actions should be taken by pilots to reduce the potential of F.O.D. during ground operations:

1, Following maintenance, ensure that the mechanic hasn’t left anything in the intake. Even a small safety wire clipping can F.O.D. an engine.
2. Avoid run-ups in areas containing loose gravel or sand.
3. Avoid use of reverse at low ground speeds.
4. Do not use reverse to position the aircraft on the ground.
5. In newer King Airs, consider extending the ice vanes just prior to landing, especially if you are planning on using heavy reverse. KingAirTraining.com