Safety First For Holdover Protection…

In the aviation industry de-icing has been carried out since Kilfrost’s founder, Joseph Halbert, invented the first ever paste back in the 1930s. (Kilfrost)

Neal Wesley, Senior Development Chemist at Kilfrost explains about the need for appropriate protection when the temperature starts to drop.

In the aviation industry de-icing has been carried out since Kilfrost’s founder, Joseph Halbert, invented the first ever paste back in the 1930s. (Kilfrost)

With the Northern Hemisphere in the midst of another cold winter, and with some parts of Europe and the United States having already experienced particularly severe weather, the question of aircraft safety is rightly at the forefront of people’s minds.
In the aviation industry de-icing has been carried out since Kilfrost’s founder, Joseph Halbert, invented the first ever paste back in the 1930s, and ongoing developments and refinements have led to the Type I fluid we’re familiar with today.  Heated before application, the orange-coloured fluids are spray-applied by ground crews to effectively remove frost and ice build-up from aircraft wings and tails, before immediately running off to leave a smooth, clean surface.
But they don’t provide any mid-to long-term protection from the subsequent build-up of ice, leaving the aircraft vulnerable to winter weather.  For this anti-icing protection, a Type II or Type IV fluid needs to be used in addition, and can be applied heated or unheated to offer extended holdover protection.  All fluids are coloured for ease of recognition so that ground handling crews and pilots can easily see the level of protection they are receiving.  Each type of fluid, and each brand, has its own guaranteed level of protection and these can be easily reviewed using a holdover chart.
Type II and Type IV fluids are spray-applied, and de-ice on contact.  The performance of these fluids is manipulated by modifying their rheology profile, which allows the fluid to effectively ‘stick’ to the wing and provide an anti-icing capability, but then to also flow off the wing surface on the take-off run to leave the aerodynamic integrity of the aircraft intact.  Essentially, the fluids remain viscous to allow them to cling to the wing until the aircraft accelerates to a speed which creates enough airflow to act a sheering force on the fluid.  This destroys the viscosity of the fluid and allows it run cleanly off the aircraft surfaces.
It’s absolutely imperative that the right level of protection is provided and while Type I fluids most certainly do have a place in the safe and effective ground operations of any airport, they don’t offer significant holdover protection, so for larger airports − or those where the time between the fluid being spray-applied and the aircraft actually taking off can be measured in the tens of minutes or even the hour or more − anti-icing via a Type II or Type IV is normally used.
Without it, ice can form while the aircraft is on the ground and even a small amount of build-up can substantially degrade performance – ice on the leading edge of the wing, for example, can substantially reduce the effectiveness of lift.  Contrary to some thought, it’s not only the weight of the ice which causes issues but also the surface profile, in fact even something with the surface of the finest emery paper is enough to cause a distortion of the aircraft’s aerodynamic properties.
We’re conscious that some clients prefer to use Type II fluids for their anti-icing protection, but also that longer wait and taxi times are pushing the post-fluid application times to the higher end of the holdover thresholds.  These pressures on airports will only increase, and as the global leaders in the sector we took on the responsibility for developing a solution, so set our dedicated R&D department to work.
The result is the launch this year of the most technologically advanced product yet: the Type II Kilfrost ABC K-Plus.  Offering similar holdover protection to many Type IVs, it’s particularly effective in snow so opens up the fluid to a variety of airports which previously couldn’t consider a Type II.
As well as being used cold as an anti-icing fluid to protect aircraft surfaces against the build-up of frost, ice and snow, ABC-K Plus can be applied hot, as a one-step de- and anti-icing solution, and the fluid’s handling characteristics have also been optimised for maximum ease.  It is low foaming, easy to spray and has good storage stability; but its environmental credentials are also in place because it’s fully biodegradable, triazole-free and non-hazardous.
As the weather turns colder I’d urge airports, pilots and ground handling crews across the Northern Hemisphere to ensure they’re adequately protected.  And if in doubt about which product to use, or holdover times, just call a member of our dedicated customer support team.