Ice Protection System - Types of Ice Protection Systems

Types of Ice Protection Systems

• Pneumatic deicing boots
• Thermal
  • Electrical heating elements
  • ThermaWing
  • Turbine engine bleed air
• Electro-mechanical
  • Weeping Wing
  • Electro-Mechanical Expulsion Deicing System (EMEDS)
  • Hybrid Electro-Mechanical Expulsion Deicing System
• Passive (cover system mainly used in the telecoms and offshore domains)
  • Anti icing cover

The pneumatic boot is a rubber device attached to a wing's leading edge, invented by the Goodrich Corporation (previously known as B.F. Goodrich) in 1923. Portions of the boot are alternately inflated and deflated to break ice off the boot, de-icing the wing. Rubber boots are used on jets and propeller driven aircraft.

The Thermawing, manufactured by Kelly Aerospace Thermal Systems, is an electrical ice protection system. ThermaWing uses a flexible, electrically conductive, graphite foil attached to a wing's leading edge. Electric heaters are usually flexible enough to use as anti-icers or de-icers. Once activated an exact concentration of heat melts the bond between ice and protected surface. Ice no longer sticks to the surface due to aerodynamic forces. As an anti-icer, the heater keeps the surface warm so that ice does not form.

A bleed air system is used by most larger jet aircraft to keep flight surfaces above the freezing temperature required for ice to accumulate (called anti-icing). The hot air is "bled" off the jet engine into tubes routed through wings, tail surfaces, and engine inlets.

Electro-mechanical Expulsion Deicing Systems (EMEDS) use a mechanical force to knock the ice off the flight surface. Typically, actuators are installed underneath the skin of the structure. The actuator is moved to induce a shock wave in the protected surface to dislodge the ice. Cox and Company, Inc. of Plainview, NY developed a light weight, low power system called EMEDS that is the first ice protection technology to receive FAA certification in 50 years, and is currently in-service on multiple commercial aircraft (FAA Part 23 and Part 25) and military aircraft. Innovative Dynamics in Ithaca, NY has developed a system that's light weight and low power using actuators called EIDI.

Hybrid Electro-Mechanical Expulsion Deicing Systems combine an EMEDS de-icer with an electrical heating element anti-icer. The heater prevents ice accumulation on the leading edge of the airfoil and the actuators of the EMED system remove ice that accumulates aft of the heated portion of the airfoil. Cox and Company, Inc. of Plainview, NY has developed multiple versions of Hybrid EMED systems referred to as Thermo-Mechanical Expulsion Deicing System (TMEDS).

A weeping wing system, also known as a TKS (Tecalemit-Kilfrost-Sheepbridge Stokes) system, uses a liquid based on ethylene glycol to coat the surface and prevent ice from accumulating. The leading edges of the wings, horizontal and vertical stabilizer are made of porous, laser-drilled titanium panels, through which the fluid is pumped during flight in icing conditions. A "slinger ring" may be used to distribute fluid on propellers, and a spray bar can be used to apply fluid to the windshield. This system is commonly used on small-to-medium-sized propeller-driven aircraft, and a number of business jet aircraft. It also has some applications in military use.

The Passive systems are a new conceptual non-thermal anti-icing and pollution solution based on textile. This innovative textile has the properties characterized by a high level of water resistance which has a natural self-cleaning effect to repel water, thereby eliminating the build of ice, with a high resistance to UV radiation and harsh climatic conditions and has a durable protective function.