What methods are used to deice airplanes?

Main Points to Consider

While waiting on the runway, observing snow, sleet, or freezing rain accumulate on your car, house, or sidewalk, remember it’s also coating the airplane you’re about to board. Ice on personal items might be inconvenient, but on an aircraft, it poses a serious safety risk. The issue isn’t the weight or freezing of critical components—it’s how ice disrupts airflow over the wings, impacting lift, the force that enables flight. This is a critical factor that must remain unaffected by ice or any other interference.

Deicing involves removing ice from aircraft, while anti-icing prevents ice from re-forming after removal. Together, these processes ensure the safety of airplanes, their crews, and passengers during flight.

Deicing solutions consist of glycol and water, with glycol reducing the freezing point of water [source: Ritter]. These mixtures are tailored for various weather conditions but are uniformly heated and sprayed onto planes to eliminate snow, ice, or frost. Pilots decide when deicing is needed and supervise the process, adhering to the FAA's extensive regulations. These rules span over 30 pages, detailing everything from the composition and handling of deicing fluids to their application and required documentation.

Applying deicer requires speed and precision. The process must be executed efficiently, focusing on holdover time—the period before ice re-forms and re-treatment is necessary. This time varies based on the deicing fluid's composition and is determined by the manufacturer. With deicing compounds costing over $5 per gallon, the procedure can be expensive, making it crucial to adhere to holdover times [source: Smith]. This is why deicing is done just before takeoff, ensuring the plane is ready to depart immediately after treatment.

Deicing agents typically don’t prevent ice from re-forming. If snow, sleet, or freezing rain persists during deicing, an anti-icing application may be necessary. Anti-icing fluids contain a higher glycol concentration than deicing fluids, along with a thickening agent to help the solution stick to the plane during takeoff.

A thin, even layer of anti-icing fluid is applied when needed. The FAA recommends that anti-icing be done within three minutes of deicing and avoided if the deicing fluid has frozen or frost has reappeared. In such cases, deicing must be repeated before applying anti-icing agents.

When an airplane has only a light layer of frost instead of ice, it’s possible to combine deicing and anti-icing into a single step. In such cases, the anti-icing fluid serves a dual purpose: melting the frost and preventing further ice formation on the aircraft.

The FAA specifies that the following parts of an airplane may need deicing and anti-icing:

The ground and flight crews collaborate to determine which areas require deicing and the most effective method based on temperature and weather conditions. Typically, these procedures are carried out at the gate, but they can also be performed at remote locations. The priority is to ensure the plane is ready for takeoff promptly after the fluids are applied.

The FAA advises using two to four deicing vehicles for commercial jets. The process starts at the front of the fuselage, moves to the wings, then the aft-fuselage, followed by the vertical stabilizer, and finally the horizontal stabilizer (both located in the tail section).

Once airborne, aircraft are equipped with systems to prevent ice buildup on their surfaces. These systems are crucial year-round, as temperatures at high altitudes remain below freezing even in summer. Most commercial jets use hot air from the engines, channeled through pipes to warm the wings and tail. Other planes employ inflatable devices that break up ice accumulations. Additionally, these systems include built-in redundancies to ensure continuous ice prevention if one system fails.

While passengers often worry about delays caused by deicing, the broader implications are significant. Delays can disrupt travel for thousands globally, even in warm climates. Environmental concerns also arise, as deicing fluids are sprayed extensively, with excess often seeping into the ground.

Innovative research inspired by poison dart frogs could revolutionize deicing. These frogs have a dual-layer skin: an outer layer that detects threats and an inner layer that releases toxins when needed.

A scientist has proposed a similar deicing method for airplanes. The outer layer would be superhydrophobic, repelling water droplets. In severe weather, if ice begins to form, the inner layer would detect it and release antifreeze, targeting only the affected areas. This approach, tested successfully in labs in 2015, could replace bulk deicing but may take years or decades to implement [source: Casey].

In the meantime, remain calm and patient during deicing delays. Thanks to the FAA's rigorous procedures, ice-related airplane accidents have become exceedingly rare.