As with any strong reputation, (both good and bad) there can be an inherent danger of confusion. As related to aircraft icing, super cool water droplets are nowhere near as cool as the college professor I described earlier. These insidious water droplets are killers of aircraft and pilots, a true misnomer. A well publicized aircraft accident involving a Colgan Air commuter plane on approach in icing conditions into Buffalo, NY on February 12, 2009 illustrated this important point. The National Transportation and Safety Board (NTSB) provides an excellent animation of this fatal accident of an aircraft that was certified for flying into this type of weather condition. For more information on this accident and its aftermath, read the NTSB's accident synopsis.
As most pilots know, unlike transport category aircraft, many general aviation aircraft are not certified by the FAA to fly into what is commonly known as flight into known icing, or FIKI because the certification process of the required equipment is time consuming and expensive. To remember if your aircraft has anti-ice only equipment and/or deice equipment remember this: anti-icing equipment is turned on before entering icing conditions and is designed to prevent ice from forming whereas deicing equipment is designed to remove ice after it begins to accumulate on the airframe. The obvious danger is a layer of ice no thicker or rougher than a piece of coarse sandpaper can reduce lift by 30 percent and increase drag up to 40 percent. Even aircraft equipped and certified for FIKI are significantly affected by ice accumulation on unprotected areas of the aircraft.
Super cooled water droplets are defined by the National Oceanic and Atmospheric Administration (NOAA) as "Liquid water that is below 0°C, or water that stays in liquid form if undisturbed even though it has been cooled to a temperature below its normal freezing point. The smaller and purer the water droplets, the more likely they can become supercooled." Because these droplets are held in suspension as liquid below freezing, the primary danger of them is they freeze on impact to any surface of the aircraft as illustrated in the following graphic in step number 5 and can cause all sorts of havoc.
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| Courtesy National Weather Service |
There are numerous sources and training aid on planning for, avoiding and mitigating inadvertent flying into icing conditions. Check out NASA's Glenn Research Center web page for more detailed information on aircraft icing and complete the free training on this deadly topic. Many aviation managers and professional pilots view aircraft icing training as an essential industry "best practice" and complete it on an annual basis as any recurrent training.
Like other flying seasons, winter flying in the snow belt poses its own unique challenges that pilots must assuage. It's definitely not a time to hang up the wings for 3-4 months and wait it out. EVERY pilot should ALWAYS respect FAR 91. 527 (known as the Clean Aircraft Concept), execute proper planning and diligent methodology as essential functions for a safe and enjoyable winter flying experience. Check out Elite Aviation Training for current dates and times of our winter flying seminar, "Icing the Cake: Winter Flying Operations".
Have fun flying this winter season and leave the icing to the cake!
Tailwinds...
