How to Handle Winter Flying

Since not all hangars are heated, many aircraft owners have engine and oil preheaters—some can be turned on remotely hours in advance by a mobile device. Alternatively, external gas or electric engine heaters that circulate warm air around the engine are also popular. There are also many aircraft covers designed to work in conjunction with these devices to keep the aircraft relatively warm between flights and many have thermostats to prevent damage of overheating.

Even if the aircraft is kept in a hangar, it will likely need some form of preheating to minimize the risk of excessive wear upon start-up.

Cold also drains the life from batteries, so a battery tender is helpful to help maintain cranking power in cold weather.

Study the cold weather start procedure for the aircraft before you attempt it for the first time. There are learners who over-prime the engine, often by jockeying the throttle back and forth, and set fire to the engine or puke fuel all over the ramp.

Before takeoff, make sure the heater and defroster are working properly. If the aircraft has a carbon monoxide detector, make sure it is in good working order and that you know how to use it. There are some detectors that give the pilot an indication that there is CO leaking into the cabin but don’t give an indication of the levels.

Carbon monoxide is odorless and colorless and can overcome a person quickly. Open the air vents and find a suitable place to land ASAP.

At flight schools where hangar space is at a premium, defrosting aircraft can be a ballet of airplane movement. The aircraft that will fly first thing in the morning may be placed in the hangar overnight.

Brush as much snow and ice off when the aircraft is on the ramp because when it gets into the warmth of the heated hangar, it will make a considerable mess that also creates a safety hazard on a concrete floor. Moving tightly nested aircraft in and out of hangars is a multiperson job to prevent hangar rash. 

Learning how to defrost an aircraft should be part of winter training so it is done properly and without damaging an aircraft. Some flight schools utilize an application of isopropyl alcohol (outside the hangar). 

There is a technique to sweeping the slush off the aircraft then quickly drying the wing with a chamois cloth so it doesn’t refreeze or scratch the paint or plexiglass. 

Shop towels should be avoided as they are often too rough to use on aircraft finishes or on the plexiglass windscreen. Some may have been laundered so they may be clean but could potentially have a metal shaving or some other FOD caught in the fabric that can cause damage. If a towel is dropped on the ground, don’t let it touch the aircraft again as it may have picked up a piece of grit.

If it is sunny, aircraft on the ramp can be carefully positioned to have their tails into the sun.  Heat and time take care of the ice, but remember the aircraft should be dried off because the moisture will refreeze in the air. Aircraft that were defrosted in the hangar also need to be dry before they go outside so the moisture doesn’t refreeze.

Be wary of sublimation—a warm, dry airplane is rolled out of the hangar and onto the ramp on a dry, clear but very cold day, and within minutes ice begins to form on the skin although there is no moisture present such as clouds, mist, or rain.

Hypothermia can put you behind the aircraft before you realize that you are compromised and carbon monoxide poisoning is a much greater risk in cold weather flying because of the source of cabin heat.

In many aircraft, cabin and windshield defroster heat is generated from the exhaust manifold. A cracked manifold likely means that CO is being blown into the cabin.

If the aircraft has a carbon monoxide detector, make sure it is in good working order and that you know how to monitor it. There are some units that give the pilot an indication that there is CO leaking into the cabin but don’t give an indication of the toxic levels. Get reacquainted with the warning signs of carbon monoxide poisoning–it is odorless and colorless and can overcome a person in a hurry. If you start experiencing symptoms, open the air vents and find a suitable place to land ASAP.

Cooler temperatures mean better engine performance. If you are flying a carburetor-equipped aircraft, intermittent use of carburetor heat is a useful preventative measure. Be wary if the faces of the round dial instruments become opaque with condensation. If you cannot read them, they are useless, so you might as well land.

When you pull up a weather briefing for a training flight in the local area, include airports located at least 50 miles away from your departure point. This gives you an idea of what conditions are heading your way.

If the winds are from the south, and there is snow and low visibility to an airport 20 miles to the south of your departure point, there’s a pretty good chance that weather will be at your aircraft within a few minutes.

If you are not instrument rated or your aircraft is not equipped for instrument flight, pay special attention to how fast the weather is moving and have at least two plans for avoiding it. 

If the aircraft is equipped for instrument flight but you don’t have an instrument rating, start working on it, and in the interim, ask a qualified CFI for some dual instruction on basic attitude flying.

If the weather moves faster than anticipated and you find yourself in the clouds, don’t be afraid to declare an emergency and ask for radar vectors to clear skies or the nearest airport. 

The postflight in the winter will take longer as well. Make sure the aircraft is stowed as you found it by installing cowl plugs, engine cover, wing covers, plugging in the battery tender and or engine heaters, etc.

Based on where you live, winter flying may not change all that much. For those in the north, it takes a bit of extra planning and prep but the air is smooth, the visibility can be amazing, and aircraft performance is great.

This column first appeared in the November Issue 952 of the FLYING print edition.