Airports' Winter Runways: Salt Or No Salt?

Airports use a variety of methods to keep runways clear of snow and ice. While salt is a cheap and effective way of clearing roads, it is rarely used on runways because it corrodes the aluminium skin of aircraft. Instead, airports use mechanical methods such as snowploughs, giant spinning brooms, and brushes to keep runways clear. They also use de-icing and anti-icing chemicals such as urea, potassium acetate, and sodium formate.

Salt is not used on runways as it corrodes aircraft metal

Airports typically aim to clear frozen deposits completely using mechanical methods such as snowplows, giant spinning brooms, and brushes. They also use de-icing and anti-icing chemicals in solid or liquid form, often referred to as Pavement De-icing Products (PDP) or Runway De-icing Fluids (RDF). These products melt frozen deposits or prevent freezing or re-freezing of liquid on the surface by lowering its freezing point. Common products used for this purpose include ethylene/propylene glycol-based fluids, potassium acetate, and potassium formate.

In addition to these methods, some airports also use grit to provide a grippy surface for planes. Another technique is to heat the runways, although this is less common due to the high energy costs associated with it. Overall, the goal is to keep the airport open and safe for aircraft operations, while also protecting the aircraft themselves from corrosion.

Airports use specialised de-icing chemicals, such as urea, potassium acetate, and sodium formate

Unlike state highway departments, airports cannot use salt-based chemicals to prevent ice from forming on runways. This is because salt is corrosive to aluminium, which is the skin of most aircraft. Instead, airports use specialised de-icing chemicals, such as urea, potassium acetate, and sodium formate.

Urea is a solid ice melter that is often mixed with heated sand that meets FAA particulate (grain) size requirements. However, many airports have moved away from using urea because, in addition to being a great ice melter, it is also a very good fertiliser. This results in airports having to deal with excessive grass growth in the summer.

Potassium acetate is a liquid anti-icer commonly used to treat runways. It is very expensive. Sodium formate is another liquid anti-icer, though it is often used on taxiways rather than runways. On a single snowstorm, an airport could spend over $200,000 on chemicals to keep the airport open.

In addition to these specialised chemicals, airports also use mechanical methods to keep runways clear, such as giant snow-moving equipment, plows, and brushes.

Mechanical methods are also used to clear snow and ice, such as snowploughs, giant brushes, and polyurethane snowplough blades

While airports may use a variety of methods to clear snow and ice from runways, mechanical methods are often employed. This includes the use of snowploughs, giant brushes, and polyurethane snowplough blades. These methods are crucial in the battle against cancelled flights, with runways serving as the battlefield.

Snowploughs play a pivotal role in clearing snow and ice from runways, taxiways, and other airport surfaces. They work tirelessly to keep these areas clear, ensuring safe conditions for aircraft operations. The use of giant brushes complements the efforts of snowploughs, providing a comprehensive solution to snow and ice removal. Additionally, polyurethane snowplough blades are favoured over steel-tipped ones as they are gentler on the runway surface, reducing the risk of potholes.

The importance of these mechanical methods cannot be overstated. They enable airports to maintain surface friction, ensuring adequate braking action and directional control for aircraft. By prioritising the removal of ice and snow, airports can enhance safety and minimise disruptions caused by winter weather conditions.

In addition to mechanical methods, airports also employ de-icing and anti-icing chemicals, either in solid or liquid form. These chemicals, known as Pavement De-icing Products (PDP) or Runway De-icing Fluids (RDF), are crucial in melting frozen deposits and preventing refreezing. However, the choice of chemicals must be carefully considered, as some can cause damage to aircraft components.

The battle against snow and ice on runways is a challenging one, requiring well-choreographed plans and specialised equipment. Mechanical methods, such as snowploughs, giant brushes, and polyurethane blades, play a crucial role in this endeavour, working in tandem with chemical treatments to ensure safe and efficient airport operations during winter.

Airports prepare for bad weather with well-choreographed plans, and it takes quite a bit of snow to completely close one

Airports are well-prepared for bad weather. They have well-choreographed plans in place to deal with whatever might happen, and it takes quite a bit of snow to completely close one.

Airports do not use regular salt on runways, as it is corrosive to aircraft and can cause rust. Instead, they use various methods to clear snow and ice and maintain surface friction, including mechanical methods such as snowploughs, giant spinning brooms, and brushes, as well as chemical de-icers and anti-icers.

De-icing and anti-icing chemicals are often referred to as Pavement De-icing Products (PDP) or Runway De-icing Fluids (RDF). They are used to melt frozen deposits or prevent freezing or re-freezing by lowering the freezing point of the surface. Common types of PDPs and RDFs include ethylene/propylene glycol-based fluids, potassium acetate, and potassium formate. Airports also use heated sand, urea, sodium formate glycol, and other specialised formulas that do not affect the metal on aircraft.

The biggest priority for airports is keeping ice from forming on runways. Snow and rain are easier to deal with, but once ice bonds to the runway surface, it takes a lot of work to get back down to dry pavement. This requires constant preparation and hard work. Airports need to ensure that their runways are safe for aircraft and that there are no foreign objects, such as parts of trucks or damaged lights, on the runway. They also use measurement devices to determine the coefficient of friction of a runway to ensure that it is safe for planes to operate.

Everything at an airport slows down when it snows. Runways that usually handle a plane taking off every 45 seconds can only handle one every 90 seconds in snowy conditions. Baggage handlers must move more slowly due to slippery conditions, planes must be actively de-iced before taking off, and runways need to be shut down periodically so that armies of trucks with giant plows and brushes can clear the pavement. This means that an airport's ability to handle arriving and departing aircraft can be cut in half or worse, resulting in many cancelled flights.

De-icing fluids can have adverse effects when combined with residuals on airplanes

Salt is never used to de-ice runways at airports because it is highly corrosive to aluminium, which is the material used for the skin of most aircraft. Instead, airports use a variety of other products to combat ice build-up and ice formation on airport surfaces, such as urea, heated sand, potassium acetate, sodium formate, glycol, and more.

De-icing fluids are used to de-ice aircraft, and these come in a variety of types, typically composed of ethylene glycol (EG) or propylene glycol (PG), along with other ingredients such as thickening agents, surfactants (wetting agents), corrosion inhibitors, colours, and UV-sensitive dye.

The use of de-icing fluids on aircraft can cause problems when combined with the de-icing fluids used on runways. The residuals left on the airplanes can cause issues, as studies have shown that runway de-icing fluids, which contain potassium acetate or potassium formate-based fluids (deionizing salts), can combine with the de-icing fluid residuals on airplanes. This can lead to a more rapid formation of residue.

Additionally, de-icing fluid residuals on airplanes can freeze and cause damage to flight controls. Therefore, it is important to have an appropriate inspection and cleaning program in place when using these types of fluids.

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