Aircraft De/Anti-Icing Fluids Jennifer Black

Why are De/Anti-Icing fluids needed in Aviation?

  Prevents winter precipitation from adhering to aircraft critical surfaces

  Frozen contaminants disrupt the air flow

  Increase drag

  Decrease lift

De-Icing Fluid

  Type I

  Applied hot

  Orange

  Clean off wing

  Viscosity similar to water

Anti-Icing Fluid

  Type II, III, and IV

  Applied cold

  Green

  Prevent precipitation freezing to the wing and critical control surfaces

  Has a ‘Holdover Time’ associated with the ambient temperature, precipitation type and precipitation rate.

  Thicken to have consistency of half-set jello

Ethylene Glycol

  Organic Compound

  C2H6O2

  Toxic

  Freeze Point = -12C

  Used in countries with climatologically colder temps

Propylene Glycol

  C3H8O2

  Non-toxic

  Freeze Point = -59C

  Used at most US airports

Frigorific Mixture

  Mixture of two or more chemicals

  Equilibrium temperature independent of its components

  Used for non-mechanical refrigeration

It’s frigorific!!!

(2011, Scott)

Freeze Point Depression

  Optimal solution of 70% Ethylene Glycol and 30% water

  Freeze point of ~ -55C

  Brix measurement of amount of glycol in the fluid

(2009, DOW)

Change in Viscosity during take off

  Trade Secret ingredient

  A polymer thickener with wind speed sensitive bonds

  As wind speed increases the bonds break and lowers the viscosity

  At flight speed the fluids flows off the critical surfaces of the aircraft

  http://www.youtube.com/watch?v=JPSH2TB_bTs

Summary

  De/Anti-Icing Fluid are used on aircraft in winter precipitation

  Ethylene and Propylene Glycol

  Frigorific Mixture

  Fluid is sheered off aircraft at take-off

Questions