ICE REMOVAL PROCESSES

ICE REMOVAL PROCESSES:

 Ice may be removed by:

·         De-icing methods

·         Anti-icing methods.

  De-icing: In these methods, ice is first allowed to deposit up to a certain extent. Then system works to melt ice. System remains again ‘off’ for the ice to accrete until it de-ices again. This cyclic process continues as long as the system is made ON.

 Anti-icing: In these methods, system is ON in a known icing condition and system works not to allow any ice accretion.

  De-icing/Anti-icing Methods: There are quite a number of methods/processes employed for ice protection, such as:

Fluid method: Uses Ethylene Glycol, Isopropyl alcohol, Distilled water

Pneumatic method: Boots at the leading Edge of the wings, and stabilizers inflate alternately to break up the accumulated ice.

Thermal/Hot air method:

·         Ram air heat heated by engine exhaust,

·         Bleed air directly used by the system

 Electrical Method: Electrical heater coil installed at icing surfaces

Figure 4.5: Typical ice removal method.

Normally thermal/pneumatic/bleed air method is used in wing, tail plane and fin anti-icing while electrical method is used in windshield, windows, radomes and different probes. Liquid e.g. alcohol is used for ice removal and as rain repellant in the windshields and windows. As an example, Figure 4.5 illustrates a method of ice removal from wing main plane and engine leading edges by hot air method (anti-icing). In this system, hot air from aircraft pneumatic system is ducked span-wise along the inside of the leading edges of the wing and engines and distributed between double thickness skins. Further illustrations will be given in the next week i.e. week # 05 on de-icing and anti-icing methods.