COLD WEATHER INFLIGHT HAZARDS AND TIPS

By: Technical Counselor Dave VanDenburg
EAA Chapter 439 (Michigan)
(email: WA8DOF@yahoo.com)
www.eaa.439.org

This month I would like to discuss cold weather operations by discussing some in-flight hazards and tips applicable in the winter months.

Probably the first in-flight hazard that comes to mind when we think about winter is icing. I have flown combat aircraft in a lot of areas of the world, and short of actual combat, only two things scare me in an aircraft. One is thunderstorms (which we don’t see much of in the winter) and icing, which we do. If you see ice build up on your windshield or wings, change altitude or find clear air quickly. Don’t be afraid to use the “E” word (emergency) to get whatever help is available from ARTCC.

If you experience a reduction in RPM (fixed pitch prop) or a reduction in manifold pressure (constant speed prop) suspect induction system icing. This could be carb ice or impact ice on your air filter. If you think you are experiencing induction system icing, apply full carb heat or select alternate air. If you have carb ice, the engine will probably run rougher (as the ice melts) but will clear up soon. I do not recommend using partial carb heat unless you have a carb air temp gauge. Partial heat may increase the carb ice problems.

If you are flying behind a constant speed prop, cycle it every 30 minutes or so to keep warm oil in the dome. A sluggish pitch change mechanism could be slow to react and result in an engine overspeed during a rapid power application. This could be real expensive (and dangerous).

Switch fuel tanks with plenty of fuel remaining in the tank. If you have a frozen valve and cannot select the full tank, you will still have enough fuel to land safely. If you wait until the engine coughs, and then find you cannot move the selector valve, you will probably call yourself a few bad names and join the ranks of those called “Glider Pilots.”

Avoid power off letdowns. A high speed, idle, descent can result in very rapid cooling of your engine (shock cooling) and cracked cylinder heads. Lycoming recommends a maximum temperature change of 50 degrees F per minute. Keeping the engine leaned until you are approaching pattern altitude can also help keep your engine temps up.

After landing, run your engine at a low power setting for several minutes prior to shutdown. This also promotes slow cooling and will reduce oil cooking if you are turbo supercharged.

Lastly, I highly recommend you carry some form of survival kit. It would really stink to survive an off airport landing and then freeze to death before someone found you. Some of the things I recommend are space blankets, some duct tape, matches, an aluminum cup, knife, freeze dried coffee, tea, signaling mirror (a CD works great) and warm clothing to include a hat and gloves. Also carry a hand held radio.

These have been just a few ideas to consider when flying during the winter months. Lycoming has some cold weather tips in their book “Key Reprints.” This book is available free online at www.lycoming.textron.com. Your POH is also a great source of cold weather operating tips.

Winter flying is fun and can be just as safe and enjoyable as summer, if we take a few precautions.

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