Icing is one of the most hazardous threats in aviation. Here are advantages, and disadvantages, of common de-icing equipment.

1) Pneumatic De-ice Boots

Advantages:

Because de-ice boots use compressor bleed air, you will never run out of de-icing protection. Most aircraft equipped with de-ice boots have manual or automatic modes, which will cycle different sections of the boots for ice removal.

Disadvantages:

When you inflate the boot, you are changing the aerodynamic characteristic of the airfoil, which increases stalling speed. There is also the risk of ice forming behind the boot, where it can't be removed by the system. Finally, Lastly, there is a risk of holes in the boots. If this occurs, they won't inflate properly, and your ability to remove ice will be decreased.

2) Weeping Wings

Advantages:

One major advantage of weeping wings is its ability to protect the entire airfoil surface. As TKS fluid is pumped out from the leading edges, it runs back across the top and bottom of the surface, forming a layer of protection against ice.

Disadvantages:

You can only carry a finite amount of TKS fluid, and you'll eventually run out of it. Even in icing conditions, you still need to consider what your plan-of-action will be so you don't run low on fluid (most TKS equipped aircraft, have 1.5-2.5 hours of protection in normal conditions).

3) Bleed Air Heated Surfaces

Advantages:

Using bleed air to heat the leading edge surfaces can be very efficient. As long as your engine is running, the bleed air from the turbine section will be hot enough to prevent ice from forming.

Disadvantages:

If you turn on the heated leading edges too late, there is a risk for runback, which could freeze aft of protected surfaces. If you don't turn the system on in time, you can also have chunks of ice break off of the engine cowl and get ingested into the engine. Another disadvantage, just like de-ice boots, is its penalty against performance.

4) Electrically Heated Surfaces

Advantages:

Surfaces like jet windshields are quickly provided with de-ice and anti-ice protection regardless of engine operation. Since they are electric, unless you have an electrical failure, you will always have anti-ice and de-ice protection on the surfaces.

Disadvantages:

Electrically heated surfaces, such as the alpha vanes on large aircraft, windshields, and pitot tubes can be damaged if the heating device is left on during ground operations. Another disadvantage is their inability to heat large areas, such as wings and tail surfaces.

5) Electro-Mechanical

Advantages:

Electro-Mechanical Expulsion Deicing, or EMEDS, detects ice via a sensor. When ice starts to accumulate, coils behind the leading edge skin start to vibrate, causing ice to break off. Because it doesn't modify the airfoil surface, the system doesn't increase stall speed. Another advantage is its relatively low power requirement for operation.

Disadvantages:

According to Cox and Company, the equipment must be built into the airframe, so this technology won't see larger commercial aircraft for a while. They have started developing it on smaller aircraft such as the Raytheon Premier 1 corporate jet. Another disadvantage is its applicability on all surfaces. Because shedding ice into the engine is a bad idea, heated leading surfaces must still be used on cowl inlets.

Have you flown any of these systems? What's your preferred de-ice/anti-ice system? Tell us in the comments below.