Flying in the winter can be one of the most spectacular experiences there is. Especially in the mountains. But winter time means that we have to take special preparations to safeguard ourselves and the aircraft, so that flying remains fun even in the cold season.

Taxiing and taking off from icy or snowy run and taxiways can be difficult. Even in flight a number of situations like carburettor ice or precipitation can make live tempting. On this page we address some of these situations.

Taxi

In the winter special problems arise like trying to taxi on frozen, ice of snowy surfaces with almost or no braking action available, steering could be a problem too (certainly for a taildragger). It is important to try to remain out of pot holes, heavy snow patches, slush and the like. Wheelpants fill up easily with with show adding to the weight and possibly freezing the brakes.

Fog can be a problem too. Early morning departures with freezing fog (common with airport not close to the sea) and running propellers can create ice build up on the propellers and result in heavy in balance. Just wait it out until the fog lifts.

Taking off

At any indication of frost on the aircraft, check the wings and clean them. Do not try to take off. The properties of the wing are altered by frost and the stall speed is increased. Snow or ice on the wing reduce lift and the aircraft is increased. Frost can sometimes hardly be seen but the result is that the airfoil is changed and with that the flying capabilities of the aircraft.

With propeller aircraft the left turning tendencies (with engines that rotate clockwise) are more pronounced due to slippery surfaces, be prepared and advance the throttle more slowly than you are used to.

In flight

Carburettor Icing Conditions

Two types can develop here: fuel / throttle and induction ice. Evaporation of fuel causes a drop in temperature, when enough moisture and the temperature drops below freezing (in the carb throat) ice will form on the throat of the carb, causing a restriction. It is imperative to understand that this can happen in summer too! It all depends on temperature drop and moisture content. Throttle ice forms on the valve. Apply full carb heat when an unexpected RPM drop or MAP change (constant speed prop) sets in.
Induction ice forms when flying in circumstances where ice will form on the induction system restricting the flow of air to the carb. Applying carb heat doesn't work here, the use of alternate air is the only solution.

To prevent the build up of ice, use carb heat periodically. Like every 15 minutes or so and apply it for 30 seconds so that any ice can melt. Try to make a habit of this procedure by doing this year round, it will save the day. If you have a carb temperature indicator then apply enough carb heat to keep the carb temp above 5 Celsius to avoid icing.

If ice was present in the carburettor it will melt due to applying carb heat and the engine will momentarily run rough as it tries to run on water, which it wasn't designed to do. When the ice is removed RPM will rise and MAP too.

For engines with a fuel injection system the selection of alternate air is the solution when icing is suspected. Keep it on until entering an area with warmer air. Make sure you are aware of the freezing level, descent below that if necessary.

Precipitation in winter time is frozen above the freezing level and usually just plain wet below that. Only aircraft allowed to fly in known icing conditions can legally do so, it may not be smartest thing to do, however. Rain can turn to snow real quick and hide important navigation details on the ground. Whiteout occurs when the snow covered terrain blends into the overcast sky. Any horizon is very difficult, if not impossible to see. If this happen (like inadvertently flying into clouds) go to instruments, make a 180 turn at rate one and fly back.

Landing

Descending for landing through a thin cloud or fog layer can result in a reduced forward visibility to several hundred feet or less. While above that layer the horizontal and vertical visibility are quite good. This could be even worse when the landing runway is located into the setting sun.

Landing on wet, snow covered surfaces should be done at the minimum speed possible for the situation, not downhill, keeping the aircraft straight with the rudder. Do not use the brakes, locked wheels will result in loss of directional control. With a taildragger, keep out of heavy snow patches or shallow depths. It could nose over.

After landing

Refuel the aircraft to minimize the change for moisture formation in the tanks during the night. Have it parked in a hanger, if possible. If left outside, use the control locks and tie it down to the ground. Use control locks on the steering column or external between the flaps and ailerons, do remember to lock the rudder and elevator too. If you have wing covers, use them to keep the wings clear. Any snow on the aircraft changes its weight and if too much gets on the tail, the result could be an aircraft sitting on its tail feathers.

If your aircraft needs to cover any inlet, use the bright orange types. They are highly visible and the change of forgetting them the next day is minimized, it could be a surprise to notice on take off that your airspeed indicator isn't working (check airspeed alive on the take-off roll).

If heavy snow is expected during the night and the aircraft sits outside, be prepared to regularly clean the wings. This avoids too much weight on the structure.