Preflight Planning................................................3-1 Introduction ...................................................................3-1 Purpose of Flight............................................................3-2 Weather ..........................................................................3-2 Navigation......................................................................3-4 Performance Planning ....................................................3-8 Special Conditions .......................................................3-10 Cold Weather Flying ................................................3-10 Mountain Flying ......................................................3-11 The Ground Crew .......................................................3-11 Flying in New Territory ............................................3-12 Equipment ................................................................3-12 Personal Preparation ................................................3-13 Chapter Summary ........................................................3-13 Weather Theory and Reports .............................4-1 Introduction....................................................................4-1 The Atmosphere.............................................................4-2 Composition ...............................................................4-2 The Standard Atmosphere ..........................................4-2 Measurement of Atmospheric Pressure......................4-3 Temperature....................................................................4-3 Temperature Scales.....................................................4-3 Temperature Variations ...............................................4-4 Temperature Variations with Topography ...............4-4 Temperature Variation with Altitude.......................4-4 Heat Transfer ..............................................................4-4 Radiation.................................................................4-4 Conduction..............................................................4-4 Convection..............................................................4-5 The Adiabatic Process ............................................4-5 Air Masses .....................................................................4-5 Characteristics ............................................................4-5 Pressure Systems .......................................................4-6 Fronts .............................................................................4-7 Types of Fronts ...........................................................4-7 Cold Front ...............................................................4-7 Stationary Front ......................................................4-9 Occluded Front .......................................................4-9 Surface Fronts .......................................................4-10 Winds and Currents .....................................................4-10 Atmospheric Circulation ..........................................4-10 Coriolis Force ......................................................4-11 Pressure Gradient..................................................4-11 Surface Friction.....................................................4-12 Wind Patterns ...........................................................4-12 Convective Currents .................................................4-13 The Jet Stream .........................................................4-13 Local and Small-Scale Winds .................................4-14 Gradient Winds .....................................................4-14 Orographic Winds.................................................4-14 Anabatic Winds ....................................................4-14 Katabatic Winds ...................................................4-15 Clouds ..........................................................................4-15 Cloud Formation.......................................................4-15 Ceilings and Visibilities ...........................................4-18 Ceiling...................................................................4-18 Visibility ...............................................................4-18 Temperature/Dew Point Relationship...........................4-18 Fog............................................................................4-18 Fog Formation.......................................................4-19 Fog Types and Characteristics ..............................4-19 Atmospheric Stability and Instability ..........................4-20 Types of Stability......................................................4-20 Effects of Stable and Unstable Air ...........................4-21 Weather Hazards ..........................................................4-21 Turbulence ...............................................................4-21 Thermal.................................................................4-21 Mechanical............................................................4-22 Frontal ...................................................................4-22 Wind Shear ...........................................................4-22 Obstructions and Wind .............................................4-23 Mountain Wave.....................................................4-23 Rotors....................................................................4-24 Thunderstorms..........................................................4-24 Structure of Thunderstorms ..................................4-25 Stages in Thunderstorm Development..................4-25 Minimum Factors .................................................4-27 Summary ..................................................................4-27 How to Obtain Weather Information ...........................4-28 Sources for Weather Information ............................4-28 FAA Flight Service Stations (FSS) ......................4-28 Internet Sources ....................................................4-28 Interpreting Weather Charts and Reports .................4-29 Surface Analysis Chart .........................................4-29 Weather Depiction Chart ......................................4-31 Radar Summary Chart (SD)..................................4-31 Composite Moisture Stability Chart .....................4-32 Stability/Lifted Index Chart..................................4-32 Constant Pressure Analysis Charts ......................4-33 Significant Weather Prognostic Charts .................4-34 Additional Weather Information ..............................4-34 Skew-T Plots .........................................................4-34 Velocity Azimuth Display (VAD)Winds ..............4-35 Aviation Forecasts ...................................................4-36 Winds and Temperature Aloft Forecast.................4-36 viii Chapter 3 Chapter 4