CATEGORY ： Aviation Technology 12 Meteo Icing 2007/02/28 Wed TB ： CM ： 0 △

A. Icing in Clear Air

1. Hoar frost a) white, feathery and crystalline b) formed by sublimation c) caused by moist air coming in contact with a cold surface 2. Frozen dew a) solid surface, not feathery b) results from condensation freezing 3. Carburetor ice a) cooling by expansion, evaporation of fuel b) temp near freezing in moist air ( temo can be several degrees above freezing)

B. icing in Cloud and Precipitation

1. Souce a) supercooled cloud drops, drizzle drops or rain drops b) water can stay in liwuid form down to -40℃ 2. Rate of catch - the amount of sipercooled water interceoted by the aircraft in a given time - depends on: a) liwuid water content of the air b) size of drops - large drops imoinge while small drops follow the airstream over the wing c) airspeed - the higher the speed the greater the rate of catch d) properties of the air craft surface i.e. sharp edge

C. Two Types of Aircraft Icing

1. Rime icing a) opaque, whitish, pebbly and granular b) brittle and porous c) airvraft akin remains well below freezing 2. Clear icing a) clear, glassy and hard b) will spread after initial contact to dorm a solid sheet of ice c) temperature of sking at or slightly below freezing

D. Effects of Icing

1. Adds weight 2. Destroys 3. Obscures vision 4. Covers antennae and instruments 5. Cobers air intakes 6. Propellers

E. De-icing

1. Mechanical 2. Electrial 3. Fluids