Deep Winter Flying

Today really warmed up, it's currently 7 degrees Fahrenheit outside and I'm happily roasting my bare feet near the wood stove. Earlier, when it was colder, I was out playing with airplanes. Tomorrow's forecast high is a whopping 1 degree Fahrenheit.

Once again we find ourselves in that most enchanting portion of the year following the winter solstice, and usually ending around the first week of February, where even though the days are once again getting longer, it's as if no one or no thing, has the energy to shake off the cold. Personally, I love this time of year. Do I relish the summer? Who doesn't? But that doesn't change how much I enjoy this particularly narrow season.

What is deep winter? Well, it's what I consider the polar opposite of the dog days of summer, and in some ways it's miserable, but in others, it's delightful, if like a dog in the heat of a summer, you don't put yourself in a need to hurry.

Even getting to the airport can be a challenge. Is the access road plowed, is the runway drifted in, do we need to dig out the hangar door?

This is the time of year that no matter how well you scrape an apron with a blade, you just can't get the frost out of the asphalt. It's so cold that even with fancy gloves on, a fuel hose sucks the life right out of your hands if you need to fill the tanks.

It's also so cold that the sky sparkles. Yes, it literally twinkles, and sparkles, and glitters as though everything is electric. I've heard this phenomenon referred to as 'tricky fog' in Alaska. It's a wonderful thing to see, but it can turn into a cloud too, and fast, hence the 'tricky' part. Just as easily, it can dissipate altogether.

Inversions are common this time of year. With them come the haze and smog, byproducts of industrialization across the Pacific, but also of our beloved wood stoves, trucks, and burn piles, not to mention dust which is perfectly natural and sometimes carried around the earth, only to settle in these pockets of deep cold in the absence of spring rains that knock the dust down.

The airplanes have to be plugged in. Not just the engines. Cabins and cockpits get heated too, since avionics don't take too well to spooling up when they're cold soaked. Better yet, keep her in a heated hangar, but beware of frost when you pull her out, and of course a tiny bit of water in the tanks will turn to ice, and clog a fuel system. Don't forget to sump inside, if the sump sticks out in the cold, you might be there for a while with your finger plugging the hole. Alas, the argument continues, is it better to hangar, or better to cover?

If it's snow covered, it's a pro will use a soft bristled broom to sweep off the deep stuff before flooding a hangar floor with meltwater, or using lots more glycol from the de-ice truck.

Rivers that normally are resistant to freezing, due to their fast moving nature, readily freeze over. Today for example, the Yellowstone River, east of Big Timber, MT looked as though you could drive a truck across it without the least bit of concern.

East of Big Timber, MT the Yellowstone River is starting to freeze up. in the background is the mighty Absaroka-Beartooth Wilderness shrouded in weather.

Sometimes late at night when the temperature really plummets, things freeze that you wouldn't normally expect. Like water mains, and trees. Yes, exploding trees are a thing. The sap expands, and CRAAAACCCCKK!!! For pilots we have other things to be concerned about, earlier this week for myself and a friend it was frozen brakes that were warmed during deceleration, only to ice up because of blowing snow accumulated during the taxi back to the hangar. Thawing them out turned into a fun project.

At the northerly latitudes, it's normal for National Weather Service to put out Cold Air Aloft products which are then included in aviation forecasts, and provided to controllers as an aid to situational awareness. Why do we need someone to tell us about this cold air? Because Jet Fuel, at minus 65 degrees Celsius begins to gel. For airplanes without tank heaters, this is a real concern, because how does an engine continue to run if it can't get the fuel it needs? Most modern jets have tank heaters, so the practical impact of this cold air is not as significant as it once was. AvGas is a bit more cold tolerant than jet fuel, but I don't know of many people flying piston powered airplanes in those temperatures, at least not since the days of jet travel - in WWII and the postwar years, it was commonplace to chug along with big radial engines regardless of the temperatures.

Have you ever seen the stars from cockpit windows, above the haze layer, on a moonless winter night? It's brighter than you would guess, especially if there is a fresh snowfall. Throw a full moon in the same conditions and you can just about read a newspaper.

One more thing about flying this time of year is that not many people are out doing it. Winter flying is a lot of work, but for the work put forth, it's difficult to find a more rewarding experience than cruising along in the twilight over the still earth enjoying the company of some close friends.