What is Aircraft Deicing?
Aircraft deicing and anti-icing are the processes in which frost, snow, slush, or ice (all known as ‘frozen contamination’) are removed from an aircraft to ensure components and surfaces are kept clear.
These forms of frozen contamination can be particularly common during winter operations, and they pose a real risk to flight safety. Their presence on surfaces can directly inhibit aircraft lift capability, especially in the initial take-off phase of flight – and so procedures to prevent frozen contamination are heavily regulated and important to maintaining safety in aviation.
Read on to find out why aircraft de/anti-icing is so fundamental, all about the equipment, processes and procedures involved, and the services Miles Aviation Consulting Ltd and our team of de/anti-icing and ground operations specialists can provide for you.
Why is deicing important?
Put simply, aircraft cannot safely fly if surfaces, particularly wings and horizontal stabilisers, are contaminated with ice. This causes an irregular air flow and reduces an aircraft’s ability to create lift. Deicing and anti-icing procedures ensure that colder weather (typically winter operations below 0°C) do not impede either aircraft operations or safety. The importance of deicing cannot be understated.
There have been a multitude of aircraft incidents, many of which have resulted in fatalities, due to the failure to remove ice and frozen contaminates prior to flight. As such, this, and cold winter operations overall, are highly-controlled aspects of aviation safety. Airlines and operators are required to follow strict standards and procedures. Generally, de/anti-icing is considered one of the more skilled ramp-handling activities due to its particular safety-critical nature.
Industry operational standards for aircraft deicing and anti-icing treatments are determined by SAE International in documents AS6285 and AS6286.
Who’s involved with aircraft deicing?
Aircraft de/anti-icing is considered a ramp-handling activity and as such is generally undertaken by Ground Handling Service Providers (GHSPs), Fixed-Base Operators (FBOs), self-handling airlines, or airport operators. Any organisation offering the service is known as a ‘Deicing Service Provider (DISP).’
Annual training and refresher courses are required to undertake de/anti-icing and to remain compliant to industry standards. These should include management, instructors, and of course front-line spraying staff.
The de/anti-icing process
British Airways Winter Operations deicing aircraft at London Heathrow
Generally, deicing and anti-icing treatments take place on aircraft parking stands, however, many airfields also have specifically-designed remote deicing pads. The most common method of removing frozen contamination is to apply heated and unheated de/anti-icing fluids, sprayed on by a deicing vehicle or ‘rig’. Mechanical methods, such as using soft brushes or warm air, are also acceptable although not commonplace.
Deicing fluid is used to remove contamination, whilst anti-icing fluid is applied to prevent surfaces from freezing or re-freezing. The process can be done either in one step, whereby a single coat of heated anti-icing fluid is used to both remove contamination and prevent refreezing or in two steps. This requires contamination to be removed via application of heated deicing fluid, followed by a repeat application of a (normally) cold anti-icing fluid as well as post de/anti-icing checks to ensure aircraft are, in fact, free from frozen contamination. To find out more about de/anti-icing fluids and the different types, check out our blog here.
A key concern with the deicing process is that the fluids used (most commonly, forms of glycol diluted to various concentrations) are toxic for the environment, therefore, many operators look to capture and recycle the fluids to prevent them from reaching local water systems and habitats. Drainage systems are often used to do this - this can be a key benefit to purpose-built remote deicing pads.
Safeguarding and ensuring effective anti-icing prior to departure
In a perfect world, aircraft would all depart on-time and delays would be non-existent. However, in the real operational aviation environment, and particularly in the midst of post-COVID resource shortages, delays will occur. Operational plans should allow for this, with procedures in place to ensure safety-critical concerns, such as frozen contamination and ice, do not occur.
In the de/anti-icing world, ‘holdover time’ (HOT) is used to ensure aircraft surfaces remain free from contamination at all times prior to departure. Holdover time is the time in which anti-icing fluid is active and providing sufficient protection. Prior to departure, an ‘anti-icing code’ must be passed to flight crew to allow them to calculate the HOT, and this confirms to crew that the aircraft has been adequately anti-iced.
Upon expiry of HOT prior to departure, de/anti-icing must be repeated. These procedures safeguard aircraft in winter operations and ensure the presence of ice is eradicated and cannot affect aircraft operations. This is another benefit to remote deicing stands which are typically located closer to runways, allowing the anti-icing process to occur closer to departure times and, thus, reducing the likelihood of HOT expiry.
Deicing and anti-icing are fundamental to safe winter operations
To summarise, aircraft de/anti-icing treatments are crucial to ensuring safe winter operations. Past accidents and incidents have shown the dangers of ice, snow, slush, and frozen contamination as a whole - and, as such, these procedures and processes are heavily regulated. The use of deicing and anti-icing fluids to both remove and prevent frozen contamination, as well as safeguards to confirm aircraft are always free from contamination, ensure that colder weather is not a factor which affects safe and efficient aircraft operations.
SAE International set the standards for deicing and anti-icing, which are adopted by National Aviation Authority (NAAs) who, in turn, regulate Deicing Service Providers (DISPs) and ensure regular training is undertaken whilst operators remain compliant. Deicing and anti-icing are skilled processes performed by qualified ramp personnel, and as stated, are fundamental to safe winter operations.
Further reading: ‘All About Aircraft De/Anti-icing Fluid Types’
Would you like more information about aircraft de/anti-icing, and the services we at Miles Aviation Consulting can provide?
We are specialists in de/anti-icing, ground operations and ground handling - and can provide your organisation with high-quality training courses, documentation and ground operations manuals, audit services, and consulting/project support. If you have a bespoke requirement and think we can help, don’t hesitate to get in touch with our team.
Did you know…
We provide high quality training courses in de/anti-icing processes, including management training, instructor training, and front-line operator training. See our course pages below to find out more about our specialist de/anti-icing training offering:
