Cold-Weather Prep


rplanes seem to like cold weather, better than any other season. They pick up speed more rapidly on takeoff roll, and lift off with less effort. The controls seem to react more quickly, with a firmer feel. Engines produce more power than on a hot, soggy August afternoon. The fact is, cold air and airplanes do well together. Well, most of the time. There are a few drawbacks.

There is, of course, the problem of airframe icing, which we have addressed in these pages. But thats not what I want to talk about.


If your bird is parked outside, it can get loaded up with snow and ice, all of which must be removed before hitting the starter. Once you get rid of the cold stuff that sticks to the wings and airframe, youre really only halfway home, so to speak.

This is especially true if the airplane was put into a warm hangar to melt the accumulations, then rolled or flown into freezing temperatures. The ice, of course, melts and works its way into control surface hinges, gaps and cables. As soon as the airplane is moved back into freezing temperatures, things can freeze up again.

Aerodynamic flutter can result from ice or snow collected inside control surfaces. These surfaces have been carefully balanced and a very small amount of ice can change all that careful design work. Vibration and flutter can increase rapidly to uncontrolled destruction of control surfaces, and more.

Under the engine cowling, there are a few more things to check. One of them is the crankcase breather. This tube vents the engine crankcase, preventing any internal pressures that may build from blowing out a gasket and dumping all your oil overboard. But a crankcase breather plugged with ice-from, say, frozen condensation-will do exactly that.

If youre not sure, have your mechanic point out the crankcase breather for you and be sure to check it for blockage during your cold-weather preflight. See the sidebar on page 10 for some additional details on your engines care and feeding in cold weather.

While youre under the cowling is a good time to inspect any cold-weather equipment. Any permanently installed preheat equipment should be checked for security-especially if its been used to prep for this flight. Ensuring the muffler and any heat shrouds are solid and secure will help ensure deadly carbon monoxide doesnt enter the cabin when you operate the heater.

While we dont generally advise installing so-called winterization kits-restricting cooling airflow can do more harm than good-its not a bad idea to block off part of the oil cooler. We have seen pilots use a strip of high-quality, FAA-approved duct tape to cover maybe a third of the oil cooler-of course, wed never do such an unapproved thing to our engine. Never.

Of course, youll pay extra attention when you sump the fuel tanks. While water in the fuel during the summer months certainly is something to be addressed, this situation can take on much greater significance in the winter. Water in the fuel during the winter can easily freeze, especially at altitude, blocking or restricting flow to the engine. If the quick drains wont drain, ground the airplane and investigate. Somewhere in some part of your fuel system, there is water that is frozen. You dont want any ice in the fuel system.

Another item to add to your winter checklist is to check the alternate static source for operation. Mud, slush and water that is splashed on the fuselage while taxiing can freeze instantly on contact. You will definitely need the primary static source. If it fails in flight, be sure to review what your POH/AFM says about using the alternate system.

Naturally you will go through the standard items on the airplanes checklist. You will also want to check all of the anti-icing and de-icing equipment. To resist later in-flight ice accumulation, the de-icer boots need to be wiped down with an approved anti-icing fluid. Pitot heat, windshield heat and propeller heat should also be checked carefully, following POH procedures.

In The Cockpit

After weve checked all the equipment and preheated the engine, we also need to consider the instrument panel. In cold weather, the bearings in our gyros get cold and stiff-just like the pilots-and various avionics displays can act up until they get warm. Cables controlling the engine, cowl flaps and other devices can stiffen up to the point of becoming literally frozen. Forcing them can do more harm than good.

The ideal solution is a heated hangar, even just for an overnight. Even if such a luxury isnt available, there are various options for placing a low-wattage electric heaters in the cabin, near the instrument panel.

After the engine is started, let it warm up at a low power setting. This helps minimize any damage that might be caused by still-cold oil not getting everywhere it needs to be and allows all the engine parts to slowly reach their operating tem

perature. Never use a high power setting in the belief it will warm up the engine more quickly; doing so will only accelerate wear.

Its a good idea to move slowly and take your time before taxiing for takeoff. Even if the engine and cabin have been preheated, there are always components that need a little extra time. This is especially true once the heat is removed and cold air driven by the prop starts entering the fuselage.

While youre waiting for the avionics displays to clear and the engine to come up to operating temperature, exercise the flight controls to ensure they exhibit full travel without binding. Any exceptions can mean not all of the ice and snow is gone from the airframe and is cause for immediate investigation. Dont even think of taking off in the winter with binding controls-the situation wont fix itself once cold air is moving over the airframe.

Finally, before you are ready to take off in cold weather conditions, you need to make a careful preflight of all of the equipment involved with your flight instrumentation, communications and navigation. Take your time and get it right.

Under Way

Once taxiing, use extra care to control the taxi speed, especially if theres any ice or snow on the pavement. Slower is better, since theres less chance of skidding off a taxiway. Try to avoid taxiing over ice or snow patches that can adhere to the landing gear and freeze. This is especially true if the runway is slushy. Once safely airborne, tap the brakes in an attempt to sling off any accumulations. You may also want to recycle the landing gear when flying a retractable to ensure that any contamination is minimized.

Your runup should be performed on a dry surface, if you can find one, to avoid sliding. After runup, taxi carefully to the takeoff position.

Takeoff should be accomplished along the lines of the soft, or rough field takeoff. You want a smooth, rolling takeoff. Dont stop on the runway after runup, unless directed by ATC. You dont want frozen brakes again. Smoothly applying power is important. There may be some swerving on the takeoff roll, as you hit patches of drifting snow.

The stiffer winds in winter may require immediate and full action with the rudder during takeoff to keep things pointed in the right direction. Dont forget how to use the ailerons to correct for the inevitable crosswind, if needed.

While climbing, pay attention to engine temperatures. Even though the air is colder than in summer, normally aspirated engines are generally producing more power than they were a few months ago. This means more heat you must manage.

Once at altitude, cruise can be pretty straightforward. Keep the engine temps up and stay out of icing conditions, if you filed IFR.


Once safely at your destination, winter weather can demand taking a few extra steps to ensure the airplane is ready for its next flight. Ideally, youll roll into its hangar, plug in the engine preheater and that will be that.

If youre tying it down outside, take extra care to use good ropes or chains and secure the airplane well. Winter winds can be stronger, longer, than in the summer. If a snowstorm comes along before your next flight, it can weigh down the tail and force the nosewheel off the ground-be sure to plan your tiedown scheme for this possibility. Install any control locks and cowling plugs, plus pitot and cabin covers. Remove any ice or slush that may have accumulated from landing and taxiing.

If you know full fuel for the airplanes next flight wont be a problem, go ahead and fill the tanks now. In some parts of the country, unpredictable winter weather can mean as much or more humidity than in summer and we want to minimize the possibility of water condensing inside the fuel tanks. Consider an approved fuel additive that absorbs water and is compatible with your fuel type.

In a few months, it will be spring again, and all this will be a memory.

Ray Leis holds ATP, CFII, Commercial and glider certificates, and has served as a Designated Pilot Examiner.


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