Readers of aviation magazines are likely to see plenty of articles admonishing pilots to avoid ice, with varying degrees of alarm. Some pilots may have had scary encounters to pass on, while others might talk about managing the risk to allow pilots to gain some experience with ice—while not creating an emergency in the process. Dipping toes into the water, so to speak.
During my instrument training, I managed to dip my toes into the water on a winter flight with relatively high ceilings. We were cleared to 3,000 feet after takeoff and entered the clouds around 2,500 feet. Realizing it was cool and we were going into the clouds, I turned on the Cessna 172’s sole anti-ice system, the pitot heat, before entering the clouds. Once in the soup, I was fast concentrating on flying the gauges for several minutes while flying to my first fix and trying to dazzle my instructor. After several minutes, he asked if everything seemed normal. I thought everything was OK.
“What about your airspeed? Everything seem normal there?”
“I guess it’s a little low,” I replied.
“Look around,” he said.
Coming out of my gauge fixation, I found the windshield of the Cessna 172 coated with a frosting of ice. About a quarter inch was already on the wings, struts, and left wheelpant. That got my attention. The temperature was 35 degrees Fahrenheit at 3,000 feet, and I wondered why we were icing up when it was above freezing outside. In hindsight, I know that ice can form as much as 10 degrees above freezing, depending on conditions.
“So what are you going to do?” my instructor asked. I knew the temperature was above 40 degrees F on the ground and there were high ceilings, and I said, “Let’s descend!” A good plan, but we were IFR now and had to get permission to descend. Thankfully, the minimum vectoring altitude in our area was 2,300 feet, so the controller let us down where we soon broke out and cancelled IFR to do some pattern work.
The takeaway? The fact that I remember this lesson so vividly more than 25 years later is telling. In fact, it was one of the most valuable lessons I ever had in flying. The conditions were perfect for my instructor to teach me a valuable lesson in instrument flying, icing, and situational awareness. Mere concentration on flying instruments is not enough—you have to keep in mind the big
picture, as well.
Where will you go if you get iced up when you don’t expect it? Where’s the VFR weather in case you need to get out of it? Does the airport have an instrument approach to get you below the clouds to a safe landing? All of these are questions instrument pilots need to ask themselves continually. And perhaps most important is taking account of the type of airplane you’re flying.
A legacy Cessna 172 is simply not well armed to handle low IFR weather and icing. Mine only has a single vacuum pump, which, if it quits, will likely create a partial-panel situation in minutes after the gyros spool down. I’ve since added an Electronics International UBG-16, which among many other features instantly alerts you with a flashing red light if the vacuum pump quits. In such an event, I don’t have to notice that nickel-sized suction gauge in the panel pointing to zero.
And as for icing, a heated pitot tube will only keep your airspeed indicator working. The rest of the airframe is going to collect ice quite well with those struts and fixed gear hanging in the breeze. Serious IFR flying requires back-up systems for vacuum or an electric equivalent to keep glass cockpits alive. Anti-icing systems vary in capability from simple propeller deice to full airframe protection utilizing pneumatic boots or weeping-wing fluid deicers. Flying in the weather requires you always to keep in mind your aircraft and what it can or cannot handle. But that’s a subject of a future column.
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