EAA Sport Aviation - January 2009

better pilot

A student of mine once set off on a one-hour winter cross-country with a cabin heater control that didn’t fully open. He reasoned that he’d be fine since it was a sunny day and a short flight. By the time he approached his destination, he was so cold he could barely complete the pre-landing checklist and was having trouble following air traffic control’s instructions.

Cracked heat muffs can allow deadly carbon monoxide to enter the cockpit. Consider putting a carbon monoxide detector in the cockpit. The monitors that change color are inexpensive and readily available.

For some aircraft, a special cowl plate is recommended for cold weather operations to limit the airflow through the engine compartment. Installing the plate will not only help keep the engine at the proper operating temperatures, but also may help keep the cockpit a bit warmer.

Always be sure to have warm clothes (including gloves and a hat) close at hand while flying in the winter. If a door or window comes ajar, even a fully functional cabin heater may not be enough, and you may need the extra thermal protection to keep flying the airplane.

Slipping Away

One of the primary challenges of winter flying is slick ground surfaces. Even at slow speeds, an aircraft has considerable momentum, so proceed with caution while taxiing on the ramps and taxiways, and look well ahead to identify potential hazards. When appropriate, look for clear areas of pavement over which to maneuver the aircraft to maintain traction and allow braking. Watch out for snow banks and berms as you do so.

A few extra precautions at the run-up pad can help keep us out of the danger zone. Again, look for a clear patch of pavement on which to position the tires for the run-up, and pay attention to prop blast (ours and others) to avoid loss of control…or contributing to someone else’s loss of it.

Some of the same strategies apply to runway operations. While it’s generally a good habit to always depart and land on the centerline, there are times when it’s appropriate to keep to one side or the other to take advantage of better traction. Even hard-packed snow can significantly reduce tire friction and braking action, and combined with crosswind conditions, it may play havoc on maintaining directional control.

Soft-field takeoff and landing techniques can be helpful in some winter conditions, especially on snow-covered surfaces. Touching down softly with a bit of power can help maintain control during the transition onto a slick runway surface.

Finally, keep in mind that surfaces that are wet in daytime sunshine can quickly turn to ice as the sun sets and the temperature plummets. Look for a telltale sheen that warns of slick surfaces, and test the brakes gingerly to verify conditions.

Retuning Procedures

Once in the air, a number of our normal procedures can benefit from an attitude adjustment. Some pilots who fly retractable gear aircraft like to cycle the landing

gear down and up an extra time after departure to help prevent the mechanisms from freezing. This can be especially important when the runway is wet or slushy, as the moisture and slush can quickly freeze when the aircraft climbs to altitude, jamming the mechanisms and preventing gear extension.

Remember too that the air can be considerably colder at altitude, and the icy blast over the airframe can cause surprises. One day, not long after departure, I realized that one of the prop controls was no longer operable. Although it had worked perfectly on the ground, cold air blasting through the cowl caused moisture in the prop control cable to freeze, thus jamming the prop control in a high-pitch (low rpm) setting. The pilot of a seaplane once suffered a similar—though more alarming— problem when freezing water in the empennage froze the control cables in place during cruise. Always be prepared for the unexpected.

Many pilots adjust cowl flaps strictly by rote. When taxiing in cold weather, it might be advisable to operate with the cowl flaps closed to maintain the desired temperature. In particularly cold conditions, pilots will sometimes keep the cowl flaps closed during climb, while closely monitoring the cylinder head temperatures. If you’re uncertain about the proper procedures, check your pilot’s operating handbook or consult a knowledgeable mechanic.

In particularly cold regions, some pilots prefer to add flaps early and fly a power-on landing approach rather than pulling the throttle to idle on final. This prevents the engine from shock cooling and ensures it is ready for go-around power if it’s needed.

Exercising Judgment

Perhaps the most important aspect of safe winter flying is to exercise sound judgment. Mixing get-home-itis with challenging conditions can be a sure recipe for disaster, as the pilots of an MU- 2 departing Jefferson County Airport (BJC), in Broomfield, Colorado, learned one wintry morning. It was still snowing, and the runway had yet to be plowed when the eager pilots attempted a departure from Runway 29. As the airplane neared rotation speed, the pilot in command lost control and the aircraft plowed off the runway, across the taxiway, and into a snow bank, causing substantial damage. To most it was a no-brainer: wait until ground conditions improve before taking to the sky.

Winter flying poses some special challenges, but through careful planning and adjustment of our attitudes and techniques, we can continue to fly safely and enjoyably.

Robert N. Rossier has been flying for more than 30 years. A former aerospace engineer and flight school manager in Colorado, he spent 12 years flying for a small airline/charter service in the Northeast, serving as chief pilot and check airman. He has been writing for the aviation industry for nearly 20 years and was the recipient of a 2001 Aerospace Journalist of the Year Award.