While South Africa is still enjoying summer, the Northern Hemisphere is in the midst of winter. This means that many aircrafts which make their way to Mzansi have to be de-iced before take-off. As one of the leading airlines in the world, KLM Royal Dutch Airlines shares exactly what happens during this process and gives insight into why de-icing an aircraft is extremely important.

Maybe you’ve been aboard a plane, just before take-off, when it is suddenly surrounded by boom lifts that start spraying the aircraft with powerful jets of fluid. Was the whole aircraft shrouded in a vapour cloud, making you wonder what was going on? Well, that was de-icing.

The de-icing process can be pretty impressive. The vapour you see comes from the heated fluid hitting the frozen wings. In combination with the bright work lights on the de-icing vehicle, it all looks quite futuristic and it all gets even more spectacular when work starts on the fuselage and you can hear the powerful jets of fluid spraying left and right.

Snow, ice, hail

Winter contaminants – ice, snow, hail, sleet, frozen mist – disrupt the airflow over the wings, affecting an aircraft’s performance - and that’s something airlines want to avoid! This is why aircrafts are cleaned a just before take-off on a cold winter’s days. The de-icing process is done with a mixture of water and glycol, heated to a temperature of 70°C.

If it snows or hails during de-icing, the aircraft is also coated with a thick, un-warmed fluid, which offers temporary protection against snow and/or hail. Once an aircraft is airborne, it has its own systems to prevent ice build-up.

The fluid that KLM uses is not toxic or harmful to the environment. All the run-off fluid is collected and neatly disposed.

Central De-icing Facility

Normally, de-icing takes place at a special facility at the airport. Once passengers and cargo are on board, the aircraft taxis over to this Central De-icing Facility, better known as CDF.

Aircrafts leave their engines running during de-icing so that they can head straight to the runway for a safe and smooth take-off. If the winter weather is really grim, causing a traffic jam at the CDF, de-icing is sometimes done at the gate.

De-icing can take anything from three to 25 minutes to complete, depending on the type of aircraft and the degree of contamination. You can imagine that an Embraer 190 is easier to clean than a snowbound Boeing 747.

Permanent staff and volunteers

There is usually group of permanent de-icers based at the airport. They ensure that aircrafts can be de-iced 24/7. They are supported by temps, who do other work when the winter weather is mild. Then, there is a team of volunteers who come into action when the weather is at its worst. At Schiphol Airport in The Netherlands, this team consists of around 45 KLM superheroes who drop whatever they are doing and pull on their de-icing overalls if things get hectic at the CDF. All of these people have earned their de-icing diploma which means they fully clued up on the strict procedures and the many legal and regulatory requirements.

KLM Royal Dutch Airlines gives more insight into the de-icing process in this video clip.