Deicing fluid

Ground deicing of aircraft is commonly performed in both commercial and general aviation. The fluids used in this operation are called deicing or anti-icing fluids. The abbreviations ADF (Aircraft Deicing Fluid) or AAF (Aircraft Anti-icing Fluid) are commonly used.

Deicing fluids come in a variety of types, and are typically composed of ethylene glycol (EG) or propylene glycol (PG), along with other ingredients such as thickening agents, surfactants (wetting agents), corrosion inhibitors, and colored, UV-sensitive dye. Propylene glycol-based fluid is more common due to the fact that it is less toxic than ethylene glycol.

SAE International (formerly known as the Society of Automotive Engineers) publishes standards (SAE AMS 1428 and AMS 1424) for four different types of aviation deicing fluids:

The International Organization for Standardization publishes equivalent standards (ISO 11074 and ISO 11078), defining the same four types.

Deicing fluids containing thickeners (Types II, III, and IV) are also known as anti-icing fluids, because they are used primarily to prevent icing from re-occurring after an initial deicing with a Type I fluid.

The main component of deicing fluid is a freezing point depressant (FPD), usually propylene glycol or ethylene glycol. Other ingredients vary depending on the manufacturer, but the exact composition of a particular brand of fluid is generally held as confidential proprietary information.

Based on chemical analysis, the U.S. Environmental Protection Agency has identified five main classes of additives widely used among manufacturers:

The amount of fluid necessary to deice an aircraft depends on a wide variety of factors. Deicing a large commercial aircraft typically consumes between 500 US gallons (1,900 L) and 1,000 US gallons (3,800 L) of diluted fluid.

The cost of fluid varies widely due to market conditions. The amount deicing service companies charge end users is generally in the range of US$8 to US$12 per diluted gallon (US$2,1 to US$3,2 per litre).

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