It's a rainy, miserable fall day with the freezing level a little lower than the minimum en route IFR altitude. I study the GFA showing the cloud levels and types in the area I'll be flying through, and decide that yes, we can do the flight in this airplane. I can climb above the level of the cloud that will carry the most dangerous ice before I reach the area that has those clouds, and destination is clear, giving a safe descent. I file a flight plan beginning with a waypoint that we always file out of this airport, because it's the end of the published departure procedure, but as we're going the other way, I don't expect to actually go there. We'll be in radar contact with ATC as soon as we're off the ground and they will vector us on course.
Except they're busy. I end up flying all the way to the waypoint, and then a little bit past on vectors, and then more vectors. Vectors to the right towards the way I want to go, and then, possibly because I wasn't climbing fast enough for the controller's liking, vectors back to the left. "Vectors" just means the controller assigns me a heading to fly. Altitude is being meted out to me in thousand foot increments, from the departure plate up to the MEA, but still not my filed altitude. We're intermittently in rain, cloud, raining cloud and between clouds. "Raining cloud" isn't a thing that I've ever heard anyone say before, but it's sort of a thing. Sometimes when you're in cloud it's quite light, but you just can't see anything around you. That would be near the top of a cloud with sunlight above. Sometimes it's dark and cold. It's usually very moist, with water running up the windshield, but sometimes it's dark, with obscured vision and pelting rain. I guess on those times I'm inside a cloud underneath another cloud that is raining. It's kind of hard to see, as I'm in a cloud.
I say to my co-worker, "you bring your sunglasses?" He hasn't. "Just wait and see," I tell him. "This is one of the most fun parts of being a pilot."
We're level now, with the outside air temperature flickering between plus and minus zero (it rounds to the nearest degree on the instrument, but must have finer gradations internally). Into another cloud. This one is bumpy, a bad sign, and it's a raining cloud, but water doesn't stream up the windshield. It freezes onto it. All this vectoring around and delayed climb has got me into the area I want to avoid. I can see the water running back on the wings and freezing in little horizontal dribbles, exactly like the icing on the edge of a cake. (I think Americans call that frosting). There's a strip of rime building forward, too. This is not acceptable. Thanks to terrific weather forecasting technology I know exactly where the tops of these clouds are. I tell the controller we are picking up ice and ask for a climb to that level, the level I had wanted to fly in the first place. We get it, breaking through the tops of the clouds, a perspective that changes them instantly from dark monsters that obscure my vision and threaten to burden my airplane enough to tear it from the sky, to a brilliant white reflector for the sun. There's nothing but blue sky overhead, and I quickly put on my sunglasses. The temperature here is below freezing, but the air is dry so the ice sublimates, passes from solid to vapour, leaving me again with a clean airplane after a few minutes.
Approaching destination, ATC advises me that there is opposite direction traffic that could be a conflict, do I want to start down now early, or arrive high? I ask for the early descent and we slip through a few wispy clouds before coming out at our destination, under clear skies. At the end of the day I update the flight time in company records and advise company that there are less than fifty hours left on the right hand vacuum pump. Vacuum pumps have to be replaced every thousand hours. I have often seen them fail early. The possibility of failure is why there are two of them, and I'm pleased that the two on this airplane are out of phase; the left one has only five hundred hours on it.