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Authored by Rich Simerson Revised 01-Apr-2010 Modified by Lt Colonel Fred Blundell TX-129 Fort Worth Senior Squadron For Local Training Rev 5.0 04-Jan-2014.
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Authored by Rich Simerson Revised 01-Apr-2010Modified by Lt Colonel Fred BlundellTX-129 Fort Worth Senior Squadron For Local Training Rev 5.0 04-Jan-2014
This Training Slide Show is a project undertaken by Lt Colonel Fred Blundell of the TX-129 Fort Worth Senior Squadron, Fort Worth, TX for local use to assist those CAP Members interested in advancing their skills. The information contained herein is for CAP Member’s personal use and is not intended to replace or be a substitute for any of the CAP National Training Programs. Users should review the presentation’s Revision Number at the end of each file name to ensure that they have the most current publication.
Objectives • Discuss how convection currents affect aircraft glide path. • Discuss wind patterns around high and low-pressure areas. • Define “freezing level” and “lapse rate” • Discuss airframe icing and its affect on aircraft performance. • Discuss carburetor icing and its affect on aircraft performance.
Objectives(continued) • Discuss the characteristics of cold, unstable air masses and warm, stable air masses. • Concerning reduced visibility conditions, state the minimums for: • VFR visibility • Cloud bases when they cover one-half the sky • How far aircraft must remain below cloud cover • Discuss the dangers of wind shear. • Describe the ‘stages’ of a typical thunderstorm and discuss the dangers of flying too close.
Weather • The most important aspect of weather is its impact on flight conditions • Safety is paramount • Navigation — Visual verses Instruments • Effects on Search • Prevailing visibility • Search visibility • Search patterns and altitudes • Information — National Weather Service, Flight Service Stations, Flight Watch, PIREP’s
Flight Precautions • Each member of the aircrew must be vigilant during all phases of flight • Assign each an area to watch • Characterize visibility in the search area to establish the proper scanning range • May be different than assumed • Visibility conditions or turbulence may increase fatigue
Weather — Circulation(Continued) • The earth rotates • Air moving north is pulled toward the east • This builds a high pressure belt about 30 degrees latitude • The northerly air flow cools and starts southward • These large circulations are responsible for mixing the air and most weather
UpwardConvection Currents • Terrain which heats up creates updrafts • Updrafts tend to keep you from descending • Normally where there are updrafts there are also downdrafts EFFECT OF CONVECTION CURRENTS NORMAL GLIDE PATH ROCKY TERRAIN PLOUGHED GROUND PAVED ROAD
GLIDE PATH DUE TO CONVECTION CURRENTS NORMAL GLIDE PATH RIVER GROWING FIELDS LANDING FIELD DownwardConvection Currents • Terrain which remains cool creates downdrafts • Downdrafts cause you to descend
Turbulence • Planning flight around high terrain requires special care • Wind currents on the downwind side can be very strong • Ridges and peaks should be cleared by at least 2000 feet Flight Path 2000 ft. Wind
H Circulation Around a High Air Sinks Moves Clockwise
Circulation Around a Low L Air Rises Moves Counter Clockwise
Lapse Rate • As altitude increases the temperature decreases at a fairly uniform rate of 3.6 degrees F per 1000 (2.0 degrees C per 1000) feet; this is known as lapse rate • Use this on hot days to determine how high you should climb to get to a comfortable temperature • At some altitude the air temperature reaches the freezing temperature of water; the freezing level
Rime ice is rougher Glaze ice is clearer Icing • Frost • Snow • Icing • Airframe (lift & weight) • Carburetor Drag Lift Increases Decreases W eight Thrust Increases Decreases
Icing The wing of a NASA Twin Otter after landing. This looks to be clear icing or perhaps mixed. Notice the runback well past the leading edge and on the underside of the wing.
Icing The rectangular device on the windshield is the "hot plate", a plate of electrically heated glass which is mounted just ahead of the plastic windshield. When ice formation is especially bad, the only view forward is through the upper two- thirds of the plate, and the area around it becomes crusted with frozen runoff from the heated area.
Carburetor Icing • Moisture in the air can condense, then freeze, blocking further flow of air and fuel to the engine. • Airplanes most vulnerable when operated in high humidity OR visible moisture with temperatures between 45F and 85F. • Most likely to form at low power settings such as in descents and approaches to landings. • Fuel injected engines are not vulnerable to carburetor icing.
Causes of Frontal Activity COLD POLAR AIR DRY AIR TROPICAL MOIST AIR
WARM AIR Cirrus Cirrostratus Altostratus COLD AIR Nimbostratus St Louis Indianapolis Columbus Pittsburgh Warm Front dust/polutants
WARM AIR Cumulonimbus COLD AIR St Louis Indianapolis Columbus Pittsburgh Cold Front
Cirrus Cumulonimbus WARM AIR Cirrostratus Altostratus Nimbostratus COLD AIR COLD AIR St Louis Indianapolis Columbus Pittsburgh Occluded Front
Clouds Altocumulus
Lenticular Clouds
Lenticular Clouds
Towering Cumulus Clouds
Mushroom Clouds
Reduced Visibility • Under almost all circumstances, VFR daytime flight requires: • At least three miles visibility • When clouds cover more than one-half the sky, cloud bases must be no lower than 1,000 ft. AGL • Search aircraft must usually remain at least 500 ft. below the cloud deck
Reduced Visibility(CONTINUED) • Fog • Haze • Snow • White out • Blowing dust • Affected by sun angle and direction • Aircrew must increase vigilance during these conditions
Wind Shear • Thunderstorms • Fronts - wind shear may advance as far as 15 nm • Air flow around obstacles Windward
Wind Shear • Two potentially hazardous situations, dangerous mainly during landing: • Tailwind turns calm or to a headwind • Headwind turns calm or to a tailwind • Critical conditions for potential low-level wind shear: • Cold Front: • After front passes • If moving 30kts or more, may exist below 5000 ft for up to 3 hours • Warm front: • Before front passes • May exist below 5000 ft. for up to 6 hours • Danger passes once front passes airport • Pilot must adjust quickly
WeatherThunderstorms Cumulus Stage Mature Stage Dissipating Stage
Flight Planning WX SourcesTelephone National Weather Service 1-800 –WX Brief (1-800-992-7433) • Standard Briefing • METARS (updated as significant change has occurred) • Terminal Area Forecast (i.e. IND) • Good for 12 hours • 3 x per day • Area Forecast (entire state or area you designate) • Every 12 hours • Route of Flight
Flight Planning WX SourcesTelephone National Weather Service • Winds Aloft • All altitudes • Notams • Current Airmets • Convective Sigmets • Cloud Tops (reported) • Pilot Reports (PIREPS) • High/Low Pressure Areas • Fronts
Flight PlanningComputer WX Sources • AOPA.org • Weather • Satellite Images • Radar Imagery • Surface Wx Imagery • Upper Air Imagery • Textural WX
Flight PlanningComputer WX Sources(Continued) • Weatherunderground.com • Temperature • Heat Index • Wind Chill • Radar • Dew point • Visibility
Flight PlanningComputer WX Sources(Continued) • Intellicast.com • Radar • Severe Weather • Satellite • Surface Analysis • Hurricane Watch • More Spam
Flight PlanningComputer WX Sources(Continued) • NOAA’s National Weather Center (adds.aviationweather.noaa.gov) • Turbulence • Convection • Winds/Temps • Prog Charts • Metars • Tafs • Pireps
JOT Time 1240Z C-172 at Fl Level 2500. Reported sky cover was overcast from 8000-10000 ft. Occasional light chop. Scattered VirgaObserved
JOT reported at the same time 1245Z showed surface weather winds from 190 at 4knots, visibility was 10sm and CLEAR! Temperature was 23C and dew point 19C
Radio Services • Flight Service Station (FSS) • Flight Watch (122.0) • Automatic Terminal Information Service(ATIS) • Transcribed weather broadcasts (TWEB) • Scheduled weather broadcasts • Fifteen minutes after the hour • Alerts, hourly weather, Advisory, Pilot Reports, Radar • Pilot Weather Reports (PIREP)
Questions? Always Think Safety!