I\u2019m telling you why<\/p>\n\n\n\n
Winter season<\/strong> is coming to town\u201d<\/p>\n\n\n\n We all know it, the winter season is coming, and we have to change our summer car tires to winter tires for a better grip during the cold season\u2026 Well, at least some of us do it. In the aerospace industry, specialized tires are irrelevant for wintertime. The focus is on de-icing and ice protection systems. While de-icing is done at the airport before a flight, ice protection systems are built into the airplane and are required by certification regulations for various critical components.<\/p>\n\n\n\n Have you ever flown during winter and had to wait on the plane in line to be de-iced at the airport before take-off? Well, you\u2019ve experienced only a tiny portion of what is required to fly under these conditions. There are four types of de-icing fluids the aircraft is sprayed with, depending on the type of aircraft and conditions. They usually have different colors for aiding in the identification of the fluid and the application of the surface with the fluid. The fluids are based on some propylene or ethylene glycol.<\/p>\n\n\n\n Depending on how harsh the season is and how many flights take off (considering Covid conditions, for example), there are over 95 million liters -or 25 million US gallons- of liquid being used for de-icing of aircraft during the year in the US only.<\/p>\n\n\n By the way, did you know that if the plane cannot take off within a limited time after being sprayed with the de-icing liquid, it has to be de-iced again?<\/p>\n\n\n\n This is called the \u201cHoldover Time\u201d and can range from a few minutes to almost 3 hours. To name a few factors, it can depend on the wind, aircraft skin temperature, ambient temperature, fluid concentration and the fluid type that is used. Type I fluid is used in most cases and has a Holdover Time of 2 to 22 minutes, Type IV fluid Holdover Time can range from 0 to 4 hours and depends strongly on the product chosen.<\/p>\n\n\n\n The FAA releases the Holdover Time1<\/sup> every year as products might improve or new products are released to the market.<\/p>\n\n\n\n But all of that is only useful as long as the airplane is on the ground and during take-off, when the fluid gets sheered off by the wind and the aircraft is free of it again. But what happens then?<\/p>\n\n\n\n What happens when rain, snow or ice hits the plane and freezes while climbing and passing through the clouds and into colder altitudes?<\/p>\n\n\n\n This is where ice protection devices come in and keep the airplane\u2019s critical components free of ice.<\/p>\n\n\n\n There are various types of systems located at multiple components which need ice protection. Some of these critical systems are engine nacelle intakes, spinners, and wings. The reason is that ice on the wings can drastically reduce the aerodynamic performance and cause flow separation and lift reduction where it is unwanted. The engine nacelles intakes are usually heated at the leading edge or lip of the nacelle. Any ice that would form and shed can damage the fan blade or any of the following components, such as compressor blades and can cause a surge or flame out and more significant damage.<\/p>\n\n\n\n![\"Image](\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/6\/2022\/10\/Airplane-ice-wing-1024x602.png\")
Aircraft ice protection: where, when and how?<\/h2>\n\n\n\n