1. Sep 2012 Lesson 4.8 Meteorology Icing & Turbulence

2. Reference From the Ground Up Chapter 6.10 & 6.11: Icing & Turbulence Pages 154 - 159

3. Introduction Icing is the accumulation of ice on an aircraft during flight or on the ground. Turbulence is the abrupt vertical movement of air.Icing is the accumulation of ice on an aircraft during flight or on the ground. Turbulence is the abrupt vertical movement of air. Icing and turbulence can create serious conditions for aircraft during flight.Icing and turbulence can create serious conditions for aircraft during flight.

4. Outline IcingIcing TurbulenceTurbulence

5. Icing Clear IceClear Ice –Glass-like coating of ice –Formed by large supercooled water droplets that freeze slowly and spread

6. Icing Rime IceRime Ice –Opaque, milky white ice –Formed by instant freezing of small supercooled water droplets

7. Icing FrostFrost –White, feathery crystalline ice –Usually formed on the ground by sublimation on clear nights

8. Icing Frozen DewFrozen Dew –Clear, crystalline ice –Dew formed in the morning freezes

9. Icing Protection FluidsFluids –Alcohol-based fluid released from leading edge of wings and propellers –Makes it difficult for ice to form

10. Icing Protection Rubber BootsRubber Boots –Rubber membrane on leading edge that pulsates –Breaks off formed ice

11. Icing Protection Heating DevicesHeating Devices –Heats ice-prone areas to melt or prevent ice

12. Turbulence

13. Turbulence Classes LightLight –Momentary, slight change in altitude and/or attitude –Occupants may feel slight strain against seat belts ModerateModerate –Slightly more intense –Occupants feel strain on seatbelt –unsecured objects move around SevereSevere –Large and abrupt changes in altitude, attitude and/or airspeed –Airplane may go out of control momentarily –Occupants forced violently against seatbelts ExtremeExtreme –Airplane tossed around violently and impossible to control –Structural damage may occur

14. Turbulence Types Mechanical TurbulenceMechanical Turbulence –Friction between air and rough ground (hills, trees, buildings etc) Thermal TurbulenceThermal Turbulence –Ground heating creates upward currents of warm air Frontal TurbulenceFrontal Turbulence –Warm air is forced over cold front, turbulence at boundary Wind ShearWind Shear –Sudden change in wind speed or direction between layers of air –Usually associated with strong inversions or fast-moving cold fronts Clear Air TurbulenceClear Air Turbulence –Unexpected, violent turbulence at high altitudes in clear air

15. Next Lesson 4.9 – Meteorology Weather Reports & Forecasts From the Ground Up Chapter 6.14.3 & 6.14.4: Aviation Weather Reports & Forecasts Pages 163 - 172