How Deicing Makes Flying Safer in Winter Conditions
It’s wintertime, and in many parts of the country, that means inclement weather, with rain, hail, sleet, and snow creating hazardous conditions. Based on the number of snowstorms and blizzards last winter, you will probably see the white stuff sooner rather than later and it will inevitably snarl travel plans throughout the course of the season.
However, imagine if you will – it’s snowing. There are already inches of snow on the ground, and more piling up by the hour. You brave the roads and make it to the airport. You check your flight info and are relieved to see your flight hasn’t been cancelled nor delayed. You make it to the gate, board the plane, and fasten your seat belt. Everything’s worked out perfectly, right? Wrong. The captain’s voice comes on over the PA system, and he announces, “Well folks, we’re just making a quick stop for deicing, and then we’ll be off.”
A plane, just like any other means of transportation, is subject to the weather, and as such needs to be treated to be able to deal with different conditions. The deicing process may delay departure, but it is an essential, safe, and ultimately necessary component of cold-weather flying.
When witnessed from afar, the deicing process resembles washing a car, albeit at a much larger scale. High-pressure hoses apply aircraft deicing fluid, or ADF, to most flight surfaces of the aircraft, with a focus on the plane’s wings, engines, and tail.
An aircraft’s wings and tail are designed with specific shapes and dimensions to provide appropriate aerodynamics for proper liftoff and flight. When snow and ice build up on a plane, it significantly alters the way that air flows over the surfaces, and this may result in loss of lift and, ultimately, a crash. Therefore, while a driver may wash a car for the sake of cleanliness, a pilot makes the decision to deice the aircraft for the safety of everyone on board.
Aircraft deicing fluids are designed to remove buildups of snow, ice, and frost from aircraft so that they may safely takeoff and fly. Currently, four types of ADFs are used for this purpose.
Type I is effective for only a short time, as it tends to come off surfaces shortly after being applied. It is typically dyed orange in order to be easily identified.
Type II fluids remain on aircraft longer than Type I, and are shed only when a plane reaches a speed of 124 mph (200 km/hr). Type II fluids are typically used on larger aircraft, and are usually a pale yellow color.
Type III fluids are a mix between Type I and Type II, and are used primarily on slower aircraft. Type III fluids are also usually light yellow.
Type IV fluids are similar to Type II, although they remain on aircraft longer. Because of this, Type IV fluids, which are generally dyed green, are increasing in use and popularity over Type II fluids.
According to a study published by Nasa in 2008, 9.5% of the total number of fatal commercial aircraft accidents were caused by icing issues. Icing is so dangerous that the U.S. Army has strict regulations about flying in icing conditions, to wit: “…aircraft will not be flown into known or forecast severe icing conditions.” Researchers are constantly looking for new and better ways of making flying under wintry conditions safer for all concerned, but the current system has effectively curtailed accidents in recent years.
(Photo: Accura Media Group)