Flight and Duty times can be broken to my understanding if it is a medical emergency, please correct me if I'm wrong tho. But I think that you will find that very few of the a/c concerned will have a full de-ice system. You may be lucky and get props only. Also the equipment in the planes will be like most other a/c in charter, no hsi, rmi, wx radar etc. Most should have a gps, and if your lucky it will be tso'd.