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An American Airlines 787 coated with snow at Chicago O’Hare (Photo: Greg Linton)

The Time-Consuming But Extremely Critical Process of Deicing Aircraft in the Winter

Just recently, Southwest Airlines had to cancel many flights out of Chicago Midway Airport due to cold weather and deicing constraints. As winter kicks into high gear, it is a given that deicing crews will be out there working hard to prevent delays and make sure passengers depart safely.

While all parts of the aircraft are designed with the notion of achieving and maintaining flight, there are several areas of an airplane that are essential to flight. These areas include the wings and the horizontal and vertical stabilizers found at the tail of the aircraft.

These areas are designed to manipulate air flow in such a way as to create lift and maneuver the aircraft. When these critical areas are covered in snow or ice, the flow of air around them is disrupted reducing their efficacy.

When bad weather strikes, airplanes are still able to take off due to a clever solution: coating the plane in a special fluid that prevents the build-up of snow and ice so an aircraft can safely take off.

There are two popular methods of de-icing that can be used depending on the weather and situation of the aircraft. One method involves a fluid to simply remove ice and snow buildup and the other involves removing ice and snow and preventing buildup.

Type I

The first method of simply removing residual ice or snow from the aircraft is done with a heated orange fluid called Type I. This fluid and other deicing fluids are colored to make it easier for deicing crews to see where the fluid is being applied and if they have missed any spots.

Type I is usually heated and mixed with water at a ratio of 40 to 60 percent depending on factors such as outside air temperature.  This fluid will then be applied to the aircraft to melt any ice and snow. If there is no additional freezing precipitation falling, this will be a one-step deicing process and the aircraft is good to go.

If there is falling precipitation, the aircraft will have to be treated with two different fluids since there is a chance that there can be significant ice and snow buildup from the time that the aircraft is treated with Type I fluid and the time it takes off.

Type IV

In this scenario, after treating the aircraft with Type I fluid, which is sometimes referred to as anti-ice fluid. Type IV fluid is green, thicker, and not heated.

This fluid is used to protect the critical surfaces of aircraft from ice and snow accumulation while the plane waits to take off. This fluid sticks to the aircraft and prevents any buildup and will eventually slide off the plane as it takes off.

Future of Deicing

Aircraft deicing causes delays at many of the world’s busiest airports. It is a process that has to be repeated every time there is ice buildup making it time-consuming and expensive.

Scientists are actively on the search for the holy grail of deicing, a compound that could be applied to aircraft once at the beginning of winter or even once in a lifetime.

If something is found, deicing delays will be a thing of the past. Aircraft will be able to avoid ice and snow accumulation and safely operate in winter weather conditions.

There are many products in development, but nothing has fully materialized as a viable option yet. Until then Type I and Type IV will continue to be some of the most reliable ways of ensuring aircraft are safe to fly in the winter.


  • Hemal Gosai

    Hemal took his first flight at four years old and has been an avgeek since then. When he isn't working as an analyst he's frequently found outside watching planes fly overhead or flying in them. His favorite plane is the 747-8i which Lufthansa thankfully flies to EWR allowing for some great spotting. He firmly believes that the best way to fly between JFK and BOS is via DFW and is always willing to go for that extra elite qualifying mile.

Hemal Gosai

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