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  • Terminal Broadcast Services/Systems

    Terminal Broadcast Services/Systems

    Introduction:

     

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  • Microbursts

    Microbursts

    Introduction:

    • Microbursts are small scale, intense local downdrafts which, on reaching the surface, spread outward in all directions from the downdraft center
    • This causes the presence of both vertical and horizontal wind shears that can be extremely hazardous to all types and categories of aircraft, especially at low altitudes
    • Microbursts may be either wet, referring to their presence from a thunderstorm, or dry, referring to their presence in clear air

     

    • Due to their small size, short life span, and the fact that they can occur over areas without surface precipitation, microbursts are not easily detectable using conventional weather radar or wind shear alert systems
    • Parent clouds producing microburst activity can be any of the low or middle layer convective cloud types
    • Microbursts commonly occur within the heavy rain portion of thunderstorms, and in much weaker, benign appearing convective cells that have little or no precipitation reaching the ground
      • Usually found beneath thunderstorms and visible rain or virga
    • Usually 1 to 2 miles in diameter; wind speeds can exceed 100 knots (10,000 Feet Per Minute (FPM)) and be accompanied by rain or other obscuring phenomena; usually lasts less than 10 minutes [Figure 1]
    • Intense horizontal outflows at low altitudes result in extreme headwind to tailwind differentials that have been recorded in excess of 200 KIAS
      • An important consideration for pilots is the fact that the microburst intensifies for about 5 minutes after it strikes the ground
    • Experience has shown that microbursts are not isolated, but usually occur in groups

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  • Low-Level Wind Sheer & Microburst Detection Systems

    Low-Level Wind Sheer & Microburst Detection Systems

    Introduction:

     

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  • Clouds

    Clouds

    Introduction:

    • Clouds provide visible indication of the processes occurring in the atmosphere
      • While there is no real requirement for a pilot to identify every cloud type by name and classification, a basic knowledge can mean the difference between a comfortable flight, and a dangerous one
      • Much like a river, as you approach you can get a feel for currents and stability by how it looks – Clouds are no different
    • Solid clouds usually indicate frontal movement while broken clouds suggest turbulence
    • Clouds are grouped by families according to their shape, behavior, and altitudes:
    • Rain clouds contain the prefix or suffix nimbus
    • Nimbus: heavy or violent precipitation
    • Cumulonimbus: thunderstorm
    • Warmer air is more humid because it can hold more moisture
    • In order to saturate air, you must evaporate or cool it

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  • Aircraft Icing

    Aircraft Icing

    Introduction:

    • One of the greatest hazards to flight is aircraft icing
      • Icing decreases lift, thrust, and range, and increases drag, weight, fuel consumption, and stall speed
    • The instrument pilot must be aware of the conditions conducive to aircraft icing including:
      • Types of icing
      • Effects of icing on aircraft control and performance
      • Effects of icing on aircraft systems
      • Use and limitations of aircraft de-ice and anti-ice equipment
    • Coping with the hazards of icing begins with preflight planning to determine where icing may occur during a flight and ensuring the aircraft is free of ice and frost prior to takeoff

     

  • This attention to detail extends to managing deice and anti-ice systems properly during the flight, because weather conditions may change rapidly, and the pilot must be able to recognize when a change of flight plan is required
  • Flights shall be planned to circumvent areas of forecast atmospheric icing and thunderstorm conditions whenever practicable
    • Individual POHs will dictate the amount of flying in icing conditions permitted
    • Significant structural icing on an aircraft can cause serious aircraft control and performance problems
  • When penetrating icing layers, do so fast at low power and low AoA
  • Taxiing near slush or water may splash on the wing and empennage and freeze, increasing weight and drag and possibility limiting control surface movements
  • If encountered during approach, increase approach speed as necessary to maintain positive control
    • Consider a no-flap or half-flap approach
    • The first ~50% of flaps will generally give you more lift for the drag while the second half of the deflections typically give more drag than lift
  • Avoid ice on runways and be careful to use BETA on wet runways
    • It may be applied but smoothly and slowly
    • Rapid acceleration may aggravate directional control
    • BETA may inhibit visibility
  • Anti-Icing: the prevention of ice buildup
  • De-Icing: the removal of ice buildup
  • Reference the aircraft operating handbook for icing specifics
    • Know important things like penetration speeds for climbs and descents
    • This sort of information will keep the aircraft pitch in such a way to minimize the frontal area for ice to stick and could prove lifesaving
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  • Weather Fronts

    Weather Fronts

    Introduction:

    • Fronts are the boundary layer between air masses (where weather happens)
    • Fronts are named according to the temperature of the advancing air, relative to the air it is replacing
    • The word ‘front’ came about during WWI during the times of trench warfare where the two opposing fronts came out and battled, similar to how the two air masses battle in a weather front

     

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  • Fog !!!

    Fog

    Introduction:

    • Fog is nothing more than a low cloud, which has its base within 50′ of the ground
    • Fog forms and is therefore dependent on the air becoming temporarily supersaturated
      • Air containing more moisture than it can hold for that temperature
      • Excess moisture then condenses resulting in fog
    • Fog can be extremely important to a pilot, especially when flying to an unfamiliar region

     

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  • In-Flight Weather Advisories

    In-Flight Weather Advisories

    Introduction:

    • In-Flight Aviation Weather Advisories are forecasts which advise en-route aircraft of potentially hazardous weather
    • Advisories can be found based on geographic location:
      • In the conterminous U.S., In-Flight Weather Advisories are issued by the Aviation Weather Center (AWC) in Kansas City, Missouri and can be found on their web page athttp://aviationweather.gov/adds/airmets//http://aviationweather.gov/adds/airmets/java/
      • For the Hawaiian Islands, In-flight Weather Advisories are issued by the Weather Forecast Office (WFO) in Honolulu
      • In Alaska, In-flight Weather Advisories are issued by the Alaska Aviation Weather Unit (AAWU)
    • All heights are referenced MSL, except in the case of ceilings (listed as “CIG”) which indicates AGL
    • Advisories use the same location identifiers to describe hazardous weather areas (VORs, airports, or well know geographical areas)

     

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  • Atmosphere !!!

    Atmosphere

    Introduction:

    • The atmosphere, simply put, is the envelope of air which surrounds the Earth
    • The standard atmosphere was defined in order to provide a common denominator for atmospheric values
      • This enables us to work from average values of temperature, pressure, and density as it relates to us (altitude above mean sea level)
    • Weather is caused from the sun and unequal heating of the Earth’s surface
      • In fact weather is a direct result from the Earth spinning
      • If the Earth were to stop rotating, there would be no weather
    • Unequal heating creates a temperature imbalance between the poles

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