No skymaster is certified for FIKI (Flight Into Known Iceing). In fact, few planes are. Many planes have deicing equipment on them. There are some Skymasters that do have boots on them, mine, for instance. Apparently, with the way that the tail works, they decided that boots were not necessary on the vertical stabilizer. Now, I have flown into accumulating airframe ice, and it is a scary experience. As it should be. When we landed, we had 4 inches of ice on the front of the radar pod. That was after shedding most of it during descent.
The plane will carry a lot of ice, and continue to fly. In my most recent long trip, back from NYC, we picked up some ice on the wing, and were able to shed it using the boots. Not the same as accumulating airframe ice, just light rime ice.
You really don't want to continue to fly in accumlating ice. Last winter, a Caravan, which is certified for FIKI, crashed because it accumulated to much ice.
Bob Cook and Jerry DeSantis have P models with boots. It is good to have boots, because it gives you time to think about how bad it is, and where will you land. The alternative, no boots, means you are in a jam, as soon as it starts to form. On the
www.superskyrocket.com site, there is an article about a SuperSkyrocket, and they talked about climbing through clouds, and picking up ice, and watching it melt in the sunshine. It takes a lot longer to melt off than it does to accumulate.
By the way, Bob lives someplace near you, at least part of the year, and I live in Kalamazoo, MI, and Jerry DeSantis lives in Battle Creek, about 15 miles east of me.
Yes, we are generally this helpful for anyone who asks a question.