Private Pilot Flight Training and Instruction Flight Training Article Library | Back To 4VFR.COM Obtaining Weather Information REFERENCES: AC 0-6, AC 00-45, AC 61-21, AC 61-23, AC 61-84 and AIM P Read reports, charts, forecasts, NOTAMS, PIREPS, AIRMETS, and SIGMETS. Makes considered decision. EX Total data required for flight, winds aloft, visibility, weather, turbulence, airport conditions, surface winds, and flight restrictions. (You may expect to interpret any one of the charts in AC 00-45C during the oral part of the flight test) Winds aloft vary with altitude. It is necessary to select the wind and altitude combination most favorable to the flight. Generally you want to fly high with tail winds and low with head winds. Forecast winds are used to find estimated headings and ground speeds for planning purposes. These are adjusted in flight for actual conditions. Winds are never exactly as forecast. Visibility and aircraft performance helps you select checkpoints at practical /useable distances. Visibilities less than three miles require flight in uncontrolled airspace 700'/1200' AGL. Lower visibilities, sometimes caused by sun position, ceilings, or terrain, makes planning for airport arrivals more difficult. Cloud conditions can prevent flying at the most preferred altitude. 1000 over/500 below limits may make necessary a higher or lower than optimum altitude. Fog ceilings may make it necessary to be off course when departing. Do not plan any flight, which may take you on top of worse than scatted clouds, into worsening weather, or between cloud layers. Turbulent conditions, such as below scattered clouds may make flying above them more desirable. Passenger comfort and aircraft control are the limiting factors. High winds cause terrain induced turbulence which are given in AIRMETS, and SIGMETS usually as occurring below a certain altitude. If flying in turbulence, it will be less severe at slower speeds. Visualize a light car Vs a heavy car crossing railroad tracks as how weight and speed affects turbulence. Light turbulence rocks things, moderate slides, heavy jumps. The yellow caution range of the airspeed indicator should be avoided usually and never entered during turbulence. Airport conditions are a seldom requested element of a weather briefing. Every airport periodically undergoes construction shutdowns or modifications, which are part of required flight knowledge. The FSS is supposed to have this information. The existence of temporary obstructions may require a change in arrival procedure. A phone call to your destination is cheap insurance. Knowledge of surface winds helps you plan both your departure and arrival. By having some idea of winds you can pre-plan your turns to checkpoints, communications, and the arrival process. Crosswinds may exceed the capabilities of your aircraft thus effectively canceling the flight. NOTAMS must be requested. They may include restrictions to flight related to disaster areas, presidential parties, military activities, or air shows. Failure to acquire this knowledge prior to the flight could create serious flight test problems since the examiner probably knows of them. See instructional material on SVFR (Special Visual Flight Rules) and flight in marginal conditions. Written by Gene Whitt Flight Training Article Library | Back To 4VFR.COM