De-icing refers to the removal of snow from a surface while anti-icing is comprehended to be the applying of chemicals that do not just remove the snow but also linger on the surface and claw back the reformation of ice to a given period. Secondly, the chemicals keep at bay the adhesion of ice to facilitate mechanical removal (Airplane Flying Handbook pg 23). De-icing is carried out through mechanical methods that include scraping and pushing by applying heat, using of chemicals that are either dry or liquid that assist in lowering the freezing point of water and lastly through the combination of this three techniques.
Anti-icing is accomplished through the application of a protective layer, using a liquid that is hard to flow called anti-ice fluid, on the surface to take the contaminate (Lankford, Terry pg 33). Frozen contaminants cause crucial control surfaces to roughen and become uneven. This culminate into an accident like a crush because when large pieces of ice part, they can be ingested into systems like propellers leading to a catastrophic failure. Since this is a very severe consequence de-icing is inevitable for purposes of safety. The process of de-icing involves spraying the aircraft with fluids based on Propylene glycol usually used automobile engines.
Propylene glycol is common compared to other de-icing fluids like ethylene glycol since it is generally regarded as non-toxic. Propylene glycol is used with a system known as containment to capture the liquid that has been used so that it does not spill to the ground and water catchment areas(Pilot's Handbook of Aeronautical Knowledge 45). Though said to be non-toxic, Propylene Glycol has negative effects in nature, since it uses oxygen when it is being broken down, and this leads to the death of aquatic life. In-flight buildups of ice are the most frequent on the leading ends of the wings or the tail and engines like propellers or blades of the fan. Aircrafts of lower speed majorly use pneumatic deicing boots on these edges. The rubber boots get inflated after given periods making the ice to crack and eventually flake off. The inflation or deflation cycle is automatically controlled after the pilot activates the system.
In the de-icing of propellers, a number of modern civil fixed-wing transport aircraft embrace the use of anti-ice systems on the leading edges of wings and engine inlets and air data probes using warm air that comes from the engine, and conduited into a cavity under the surface to be anti-iced (Van, Sickle N. D, and John F. Welch 62). The warm air heats the surfaces to temperatures slightly higher than 0 degrees Celsius preventing ice from forming.