© Getty Images

Flight delays -

Ever had a flight delayed because the crew needed to deice the plane? Take enough winter trips and it’s bound to happen at some point.

© Getty Images

The problem of ice buildup -

Most people do not give much thought as to whether ice builds up on aircraft and what the consequences of that could be.

© Getty Images

Key challenge -

But preparing airplanes to withstand icy conditions is one of the major challenges of commercial air travel.

© Getty Images

Messing with the physics -

Snow and ice can significantly affect the physics of flying, so it is very important that planes are deiced before they go airborne.

© Getty Images

The deicing process -

Deicing a plane is generally a two-step process that is completed shortly before the plane takes off. It involves deicing fluids that are made especially for aircraft.

© Getty Images

Why deicing is important -

Deicing a plane before it takes off is very important, because snow and ice on aircraft wings can decrease lift by up to 30%.

© Getty Images

What is 'lift'? -

Lift is the upward vertical force that keeps a plane in the sky. It's generated when air flows over the wings of the aircraft.

© Getty Images

Impacting control -

When an airplane’s wings are covered in snow and ice, it negatively affects the pilot’s ability to maneuver and control the aircraft.

© Getty Images

Risk of ice breaking off -

There is also the risk that ice on the wings of an aircraft may break off during the flight and damage one or more parts of the aircraft.

© Getty Images

Crucial step -

Given these considerable risks, deicing an aircraft is a crucial step in its preparation for a flight, particularly during the winter months.

© Getty Images

Deicing chemicals -

Airlines do not use the same chemical deicers that are used on roads, because the salts in these products can be corrosive and therefore damage the aircraft.

© Getty Images

Glycol-based -

Instead, there are specific chemicals produced for deicing aircraft. Generally, they consist of a water-based solution of glycol mixed with various additives.

© Getty Images

How glycols work -

Glycols are very effective at lowering the freezing point of water. They therefore make it harder for water to freeze or stay frozen on surfaces.

© Getty Images

Most common types -

The most common types of glycols used are propylene glycol and ethylene glycol. They tend to make up 30-70% of the deicing solution.

© Getty Images

Ethylene vs. propylene -

In the past, ethylene glycol was the preferred component, because it's cheaper. However, propylene glycol has gradually been adopted since the 1980s, because it is less toxic to wildlife and humans.

© Getty Images

Four fluid types -

Airlines generally use four standard fluid types when deicing an aircraft. They each have different viscosities and holdover times.

© Getty Images

What is holdover time? -

The holdover time of a fluid is the length of time it is expected to protect the plane during snowy or icy conditions.

© Getty Images

Step one -

In the first step of the process, the crew removes any existing ice or snow from the plane using a heated Type I fluid, or a heated solution of Type I fluid and water.

© Getty Images

Type I fluids -

Type I fluids are the least viscous of the deicing fluids, meaning they can be spread easily over the aircraft. Generally, they are red or orange.

© Getty Images

Thin fluid -

They are also thin enough to flow off the plane while it’s not moving, which means they can be applied to any aircraft.

© Getty Images

Step two -

In the second step of the process, the crew typically applies a Type II or Type IV anti-icing solution to the aircraft.

© Getty Images

Preventing accumulation -

This is the step that helps prevent the future accumulation of ice and snow on the wings of the plane.

© Getty Images

More viscous fluids -

Type II and Type IV are more viscous than Type I fluids, meaning that they stay on the plane for longer, helping to melt any forming frost or ice.

© Getty Images

Until takeoff -

In general, these fluids stay on the aircraft until the plane is taxiing down the runway during takeaway. By this point the aircraft has gained enough speed to remove the fluids from the plane by sheer force.

© Getty Images

The importance of the colors -

Type II fluids tend to be clear or have a pale straw color, whereas Type IV fluids are generally green. The different colors of the fluids help the crew see which parts of the plane have already been treated.

© Getty Images

Type III fluids -

Type III deicing fluids, which are formulated to flow off planes at lower speeds, are less common nowadays.

© Getty Images

Used on smaller aircraft -

Sometimes they are still used on smaller commuter aircraft, since these planes do not go as fast as standard commercial jets.

© Getty Images

Environmental considerations -

When it comes to the environmental impact of deicing planes, there are a number of things to consider.

© Getty Images

Wildlife toxicity -

For instance, ethylene glycol is toxic to wildlife. The Environmental Protection Agency (EPA) therefore requires airports to monitor their stormwater runoff.

© Getty Images

Dealing with storm water -

In order to meet this requirement, most airports collect and stream their storm water runoff on site, or they send it to a treatment facility.

Sources: (CNN)

See also: How to stay safe in snow and winter storms

© Getty Images