Aero-Tips!

A good pilot is always learning -- how many times have you heard this old standard throughout your flying career? There is no truer statement in all of flying (well, with the possible exception of "there are no old, bold pilots.") It's part of what makes aviation so exciting for all of us... just when you think you've seen it all, along comes a scenario you've never imagined.

Aero-News has called upon the expertise of Thomas P. Turner, master CFI and all-around-good-guy, to bring our readers -- and us -- daily tips to improve our skills as aviators, and as representatives of the flying community. Some of them, you may have heard before... but for each of us, there will also be something we might never have considered before, or something that didn't "stick" the way it should have the first time we memorized it for the practical test.

It is our unabashed goal that "Aero-Tips" will help our readers become better, safer pilots -- as well as introducing our ground-bound readers to the concepts and principles that keep those strange aluminum-and-composite contraptions in the air... and allow them to soar magnificently through it.

Look for our daily Aero-Tips segments, coming each day to you through the Aero-News Network. Suggestions for future Aero-Tips are always welcome, as are additions or discussion of each day's tips. Remember... when it comes to being better pilots, we're all in this together.

Aero-Tips 04.21.06

Spring brings warming air in the Northern hemisphere. You might think you’ve made it through another icing season, but beware -- if you’re flying behind (or between) engines with carburetors, it’s actually becoming more likely you’ll face carburetor ice.

Carb Ice: The Threat

Carburetor ice forms when moist air enters the narrow carburetor venture and cools to the freezing point, forming ice and choking air flow at the throttle plate. Different carb designs have differing characteristics that make them more or less susceptible to icing at a given outside air temperature and humidity, but there’s a growing hazard in spring as humidities "March" upward and air temperatures "May" put you in the prime carb ice range.

Source: Civil Aviation Safety Authority New Zealand

You can see there’s a "serious" danger of carb ice even at cruise power settings when the humidity is greater than about 50% and air temperatures run from just above freezing to as high as 60°F (15°C). There’s even a narrow range (in red on the chart) where pressure-type carburetors (common in the 1950s, and generally thought to be immune to carb ice) are susceptible.

If your airplane has a carburetor air temperature gauge use enough carb heat to keep the indicated carb temperature above freezing. Note: I was very surprised that the Carb Temp gauge in a Cessna 182 I often flew indicated freezing temperatures in springtime and even summer cruise flight. If your airplane does not have a carb temp gauge, be ready to apply full carb heat at the first sign of reduced propeller rpm or lower manifold pressure. Consider applying full carb heat any time flying in visible moisture or when humidity exceeds about 80% or so (in clear air).

Aero-tip of the day: As outside air temperatures rise, be thinking about a different sort of ice hazard. For more on carb ice see Aero-Tips 1.10.2006, "Carb Ice: All or Nothing".

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