It’s that time of year again! The weather is cooling, our car windows are frosted over and so are the windows on our airplanes.

Have you ever seen de-icing fluid? It’s kind of crazy looking, and the stuff is amazing. Today, we’re diving into the world of airport deicing fluid. It’s pretty fascinating stuff.

The Process

De-icing is the process of removing snow, ice, or frost that has accumulated on airplane surfaces. This process utilizes chemicals that will remove that buildup in the event precautionary measures weren’t taken in the form of anti-icing.

Any buildup on planes can create drag, affect the ability of the wings to generate lift, and disrupt general airflow around the aircraft. All of which can lead to a negative flight experience for all on board, to say the least.

So, this process is taken very seriously at airports and is implemented whenever temperatures are likely to reach freezing temperatures.

Airport employees operate a cherry picker on a truck; a vehicle that resembles those used to work on telephone poles. From above, they spray down de-icing fluid onto the airplanes.

Another form of de-icing utilizes heat, although this is less commonly implemented at airports. This method uses infrared heating to de-ice planes. This system is used sparingly in the US with liquids being the preferred method.

The Makeup

Primarily, de-icing fluids are made of propylene glycol and other additives, and they are typically heated. This is less toxic than ethylene glycol, which is still sometimes used because of its lower operational use temperature.

The process is complicated because de-icing fluids cannot contaminate water, though propylene glycol is not toxic. It doesn’t stick to plane surfaces, so any and all runoff must be collected. The substance consumes oxygen as it decomposes, and this is harmful to aquatic life.

Here’s what the process looks like:

These fluids are often dyed to help employees identify them easily, and identify that an aircraft has been de-iced. Fluids used in these applications are non-flammable petroleum products. De-icing fluids work best when they are diluted with water because it lowers the freezing point significantly (eutectic concentration, which means that the liquid will freeze at a lower temperature than either of the fluids in the mixture). Anywhere between 500 and 1,000 gallons of de-icing fluid is used to de-ice a commercial plane.

While the weather begins to cool, some of us are taking last-minute trips to warmer climates and tropical destinations. Now you know all the work that goes into making the aircraft taking you to your tropical escape safe and your trip possible.