Winter Wisdom

Winter Wisdom

Winter Wisdom


Flying through the pit of winter, when life-threatening wind chills and unusable runways are distinct possibilities, is not for the faint of temperament. It takes devotion to the cause to tug an airplane out onto a slippery ramp in the dark, perform a perfunctory preflight with numb fingers, and race snowstorms to the destination’s final approach course. Wintertime flying is a tiresome chore, and if you live in the balmy southlands but make occasional trips northward, you are going to be doubly challenged.
Dealing with winter’s difficulties calls for an annual renewing of dormant skills. It’s a time to dig out the engine covers that have been piled in the corner of the hangar, put the tire chains back on the tow tractor, and apply ICEX to the boots and/or recheck the deicing fluid’s level, if you haven’t fired them in anger lately. Most importantly, you’ll need to refresh your own winter-flying talents and methods.
Summertime flying is a much more casual affair. Convective weather notwithstanding, one expects to go on schedule, with little preparation. Airports are always open, daylight is in the majority, ramp attire is the same shirt you wore in the cockpit. Winter, by comparison, demands respect. You had best be prepared, or you’ll be punished.
A wise old north-country pilot once told me “Son, never fly over country you aren’t prepared to walk out of.” He meant you should carry a parka, wear boots instead of loafers, have headgear and gloves, and upgrade the survival kit in the baggage compartment. Carry some blankets for the passengers, in case the cabin heat goes inoperative. Take winter seriously.
And Then, There’s The Weather
Weather patterns in wintertime move rapidly. You may have one day of ideal CAVU conditions, during which you’ll make plans to go flying tomorrow, replaced the following day by a nasty front, which then turns into another clear day before the next system arrives. Winds, both aloft and on the surface, can be strong and shifting as high pressure and low pressure alternate over a steep gradient. The jet stream dips south of its summer tracks, and triple-digit headwinds play havoc with medium-altitude flight planning.
Our airplanes can cover a lot of territory in a few hours, often taking us from one type of air mass to another, so an easy departure might be followed by a tight approach. Going into the northern tier of states requires added preparation and rethinking of one’s options. Flying over or through multiple weather systems can require careful planning. Going east or west can mean dealing with tomorrow’s or yesterday’s weather, as well as today’s.
The good weather days are the ones that are cold and clear, miserably frigid under domes of high pressure. Warmer weather brings cloud layers and the threat of precipitation. Most of the time, you’ll find it relatively easy to top the lower layers of cloud, since the clear air is waiting no higher than the low teens. The bad news is that, if there’s any moisture about, you won’t want to linger during the climbout. Icing is going to be found at some level in those clouds, maybe even on the ground under them. Depart without delay, with everything turned on to ward off ice, and expedite your ascents and descents. Do not fool around with “just a little ice”, and don’t count on it sublimating away in the clear, particularly if the sun angle is low or non-existent.
Winter precipitation is much more schedule-threatening than summer showers. Light rain is hardly cause for concern, only dropping visibility to a couple of miles unless the air becomes saturated. Light snow, on the other hand, can immediately result in a quarter-mile of whiteout visibility, and it only takes a cloud layer as thick as a handkerchief, it seems, to generate significant snow. Down low, a snow-covered landscape blends into an indistinct cloud base with dangling tentacles of snow. Reported ground visibility might be enchantingly optimistic, compared to the forward flight visibility seen from the cockpit. Sure, you can always see the ground straight underneath the airplane in snow, as long as you’re clear of cloud, but as the intensity of falling snow picks up that circle of visibility shrinks.
When flying near significant bodies of water, be cognizant of the lake effect snowfall on the downwind side of the moisture source. As an otherwise-mild change in air mass moves across the water, it picks up moisture it can’t hold and readily dumps it the form of airport-closing amounts of snow to the south and east. Chose an alternate on the dry side of the water or far to the south.
Circling approaches are particularly risky when snow is falling; there’s nothing much in the way of visual reference to maintain orientation. All of the cockpit aids on the panel need to be supplemented with old-fashioned caution when you’re groping for an airport that passed by under the side window.
It’s quite common to encounter temperature inversions during the cold season. Cold air pools at ground level overnight, leaving the previous afternoon’s relatively-warm air floating along a few thousand feet AGL. Pollutants are trapped in the cold layer and cannot rise through the cap of warm air, reducing visibility. When moisture-laden warm air moves over the top of the stubborn cold air, raindrops falling into the sub-freezing temperatures below will become supercooled, remaining liquid until they contact a surface like your airplane, where they turn into clear ice. This freezing rain is instantaneous trouble and must be exited without delay; climbing into the warm air is traditionally the best escape, but it doesn’t always work. If trapped on the ground while freezing rain is falling, waiting it out in a heated hangar is about the only option.
Airports That Aren’t Always There
In winter, you’ll have to deal with the reality of runway closures and perhaps entire airports shut down. The storm may have moved on, but the airport remains closed while snow removal is underway. General aviation is prized for its ability to use smaller fields, giving us more destination options. However, small-town airports don’t have the big snowplows and manpower of big-city aerodromes, and they may not recover from a big storm for several days. Snow removal is an even-lower priority where it seldom occurs. Those freak snowstorms that hit the upper southland now and then can wreak havoc with trip schedules; the only plows in the county are busy clearing freeways, leaving the airport for already-overworked contractors.
Up in the snow country, of course, clearing the airport is a routine chore. But that doesn’t mean ramps and taxiways get as prompt attention as runways. Calling before you go is the best advice for winter operation. Find out if the FBOs are ready to receive traffic and what is their best estimate for the airport reopening. If you’re going to want a hangar or deicing services, get in line by making your needs known in advance.
Runway conditions are pretty much a known quantity in summertime, other than for some ponding of standing water after a rainstorm. Summer’s wet pavement adds to the stopping-distance requirement, but not by as much as the slickness of wintertime conditions. Braking action reports are to be taken seriously; know the friction-meter readings that mean trouble, starting at about 40 and above. Yes, you can land on a snow-covered runway, but how much more room will you need to get stopped? How much snow depth can you tolerate? What if you hydroplane on locked-up brakes? What if your brakes freeze from snow accumulated during parking? These are all valid concerns for winter operations.
The point is, runways can be quite variable in suitability during the winter. If you’re counting on dry pavement to meet your needs, be sure that is what’s waiting for you. Don’t forget that patches of frozen stuff may be lingering on part of the runway, even after it has been plowed.
And, have a care when taxiing. Late in the winter, some pretty impressive mountains of pushed snow will have been accumulated on the ramp edges and around the smaller taxiways. Don’t hook a wingtip on one of these moguls, or turn into a winter-tightened taxiway that can’t accommodate your wingspan as well as in summertime. Moreover, always taxi as if you had no brakes; you might not.
Be especially careful on days with flat lighting, as encountered under a gray overcast that leaves no shadows, particularly deceptive after a fresh snowfall has rendered everything a tidy shade of white. The old snowpiles fade into invisibility, allowing you taxi right into them without knowing they’re there. Fingers of loose drift accumulate downwind of these piles of used snow, and you can roll into a foot of fresh snow without ever seeing it. Throw on your taxi lights to create some shadows, even though it’s daytime.
Can we operate in the winter, safely and effectively? Sure, but it’ll take some effort to deal with the vagaries of old man winter. Operate with caution and keep your options open.•T&T

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