How Does the Anti-icing System Work in Aircraft?
When that dreaded ice begins to form on your airplane’s wings or rotor blades, gets ingested into engine inlets, or starts to affect measuring instruments such as your pitot tube, this spells danger for a pilot.
For this reason, understanding how the various types of anti-icing systems in aircraft function is very important.
Aircraft IceGuard from DTN supports your de-icing decision-making by alerting you to hazardous wing temperatures combined with forecasted precipitation. It also allows you to gain additional details regarding local wing temperatures and short- and long-term weather forecasts.
Why prevent ice formation?
There are numerous potential problems that ice formation on your plane’s wing and tail surfaces can cause during your flight. And, while the way ice on an aircraft affects its flight performance is a worthy topic for a separate blog article, in this article, let’s touch briefly on what these problems are before getting into our main subject, how ice protection systems in aircraft work.
One of the fundamental problems created by ice build-up on your plane is that it interferes with the normal flow of air as it passes over your plane’s wing surface. This interference can have the undesirable result of increased weight and drag accompanied by decreased lift and thrust. This combination of consequences has profound safety implications that you cannot ignore.
If you are an experienced pilot, you might be able to successfully compensate for this reduced performance with an adjustment in the angle of your flight. However, it is good to know that this adjusted flight angle will significantly ramp up your fuel consumption.
For these reasons and more, anti-icing and/or de-icing systems in your aircraft are essential. So let’s take a closer look at how they work.
How do anti-icing and de-icing protection systems work?
Anti-icing and de-icing systems may seem like the same thing, but they work in two different ways. Anti-icing systems are designed to prevent the formation of ice completely. De-icing systems are designed to quickly remove the ice before it can cause you a significant problem.
What are some of the specific anti-icing and de-icing methods used at present? So let’s dive into that topic, starting with the anti-icing methods.
Anti-icing systems typically use heat to stop ice from forming. These heat-related systems work by causing the moisture to evaporate into the atmosphere as soon as it touches the heated surface of your plane.
Bleed air systems – If your aircraft is turbine-powered, then bleed air systems are most likely to be the anti-icing method used. The term “bleed air” comes from the fact that air is bled off from your aircraft’s hot engines, and then this hot air is fed through to all the critical surfaces of the plane.
The bleed air system works well for larger aircraft, but because it can affect engine temperatures and reduce climbing ability, the system is not usually used in most small aircraft. If your plane is not turbine-powered but piston-powered, then a bleed air system is not used, but electrical power is most likely used to supply the heat instead.
Thermal anti-icing systems – Electro-thermal or electrical heating systems operate in a similar way to a stove element. Heating coils embedded in the plane’s structure generate heat using a controlled electrical current.
In these systems, electricity is used to heat various components on the aircraft to prevent the formation of ice. These components can include:
- pitot tubes
- static air ports
- TAT and AOA probes
- ice detectors
- engine P2/T2 sensors
- water lines
- wastewater drains
- turboprop inlet cowls
Let’s move now to de-icing systems and examine two of them.
Fluid de-icing systems – A less frequently used system is the fluid de-icing system, and it involves the use of antifreeze or a de-icing fluid solution designed to “weep” de-icing fluid to the aircraft surfaces. This system is also known as the “weeping wing” de-icing system.
Fluid is forced through tiny holes to vulnerable areas of the aircraft, including the leading edges of the wings, using electrical pumps. Then, the antifreeze solution chemically breaks down the ice.
Pneumatic de-icing systems – Another de-icing method that is common is pneumatic de-icing. Ice is removed from the leading edge of the plane’s wing using what is referred to as pneumatic de-icing rubber “boots.”
These boots are fitted at the edges of the plane’s wings. They consist of a rubber sheet bonded to the leading edge of the airfoil. These rubber boots work by rapidly inflating and deflating by an engine-driven pneumatic pump which causes them to expand and contract.
This action breaks up the ice that is forming, and the ice then falls away. Because of where the rubber boot needs to fit, this method works well on slower aircraft not equipped with wing slats. You should thoroughly inspect the pneumatic rubber boots during your regular preflight checks.
The systems discussed above are essential because, during a flight, the aircraft’s surfaces will, at times, be exposed to water vapor at freezing temperatures. If no aviation system were in place to deal with this problem, then the ice would very quickly form on the wings and other critical parts of the plane that would alter the aerodynamics of the aircraft with serious negative consequences.
(If you are a pilot who makes your own operational de-icing and anti-icing decisions, NASA offers a course that you may be interested in taking.)
There is no doubt that wintery weather conditions bring a range of challenges. Although commercial airplanes can fly even in lousy weather, unnecessary de-icing and anti-icing of aircraft costs you time and money.
DTN Aircraft IceGuard supports your de-icing decision-making by combining weather observations and forecasts with wing temperature measurements and condition forecasts.
This combination of observations and forecasts allows you to plan for icy conditions more efficiently, helping you increase safety and reduce transfer times.