initial new hire part i – basic indoctrination section 2- airman specific d. meteorology star...

Initial New HirePart I – Basic Indoctrination

Section 2- Airman SpecificD. Meteorology

Star Marianas Air, Inc.

Complete Class Roster Cell Phones OFF 10 Minutes Break every hour 1 Hour Class

Before We Start

Meteorology and Hazardous Weather

BASIC WEATHER DEFINITIONS TEMPERATURE, PRESSURE, WINDS ATMOSPHERIC MOISTURE AND CLOUDS THUNDERSTORMS ICING WINDSHEAR

METEOROLOGYOVERVIEW

BASIC WEATHER DEFINITIONS

Surface Visibility Prevailing Visibility Tower Visibility RVR AWOS ASOS Inversion

SIGMET AIRMET CWA Weather Watch Weather Warning Sig Low Lvl Prog Sig Hi Lvl Prog

Surface Visibility: horizontal distance at which a predetermined object can be seen and recognized in ambient light (determined at usual point of observation)

Tower Visibility: surface visibility observed from tower Prevailing Visibility: surface visibility equaled or exceeded in

half or more of the horizon circle (not necessarily continuous)

DEFINITIONS

RVR (Runway Visual Range): distance at which a high intensity runway light can be seen

SFC VIS vs TWR VIS: when surface vis at usual obs point or tower is less than 4 miles, the lower of the two is used as prevailing and is reported in the visibility section of observation (higher of the two is included in “Remarks” section of observation)

DEFINITIONS

AWOS = Automated Weather Observing System Designed to transmit local weather observation directly to pilot

(computer generated) Available by voice only via radio or telephone

not available from any other source AWOS access published in Airport/Facility Directory and in

appropriate Instrument Approach Procedures See AIM for format, etc.

DEFINITIONS

ASOS = Automated Surface Observation System Primary surface weather observation system in the US.

1700 systems programmed for the US. Used for METAR and SPECI reports

Available on all weather data systems and ATIS See AIM for format and use

DEFINITIONS

Inversion = Characterized by an increase of temperature with height rather than a decrease

AWW = Severe Weather Forecast Alert a preliminary message issued to alert users that a Severe

Weather Bulletin is being issued Convective SIGMET = Issued only for thunderstorms and

related phenomena

DEFINITIONS

Convective SIGMETs issued for: Tornadoes Lines of thunderstorms Embedded thunderstorms Areas of thunderstorms of level 4 intensity or higher and

coverage is 40 percent or more of the area Wind gusts of 50kts or more and/or hail equal to or greater

than 3/4 inch

DEFINITIONS

SIGMET = Issued for the following hazardous weather Severe or extreme turbulence not associated with

thunderstorms Mountain wave or CAT

Severe icing not associated with thunderstorms Widespread duststorms, sandstorms or volcanic ash lowering

inflight visibility's to less than 3 miles Volcanic eruptions

DEFINITIONS

AIRMET = Issued for the following potentially hazardous weather Moderate Icing Moderate Turbulence Sustained surface winds of 30 knots or more Widespread ceilings and/or visibilities less than 1000/3 Extensive mountain obscurement

DEFINITIONS

CWA = Center Weather Advisory issued for the following weather conditions Supplements an existing SIGMET, Convective SIGMET, AIRMET

or FA (area forecast) When the above have not been issued but reported conditions

(PIREPS, etc.) meet SIGMET or AIRMET criteria When actual or forecast conditions do not meet SIGMET or

AIRMET criteria, but reports indicate weather will adversely affect flight ops

DEFINITIONS

WEATHER WATCH = Issued when the potential for severe weather exists

WEATHER WARNING = Issued when actual severe weather is occurring

Severe Weather Criteria Thunderstorms: Surface wind equal to or greater than 50kts

and/or 3/4 inch or larger hail Tornadoes

DEFINITIONS

SIG HIGH LEVEL PROG CHART = Prognostic (forecast) chart that covers altitude range from FL240 (400mb) to FL630 (70mb) and contains the following: Location, height and speed of jet streams (polar and subtropical) Height of tropopause Areas of

CB (thunderstorm) tops moderate or greater turbulence

Position of fronts at the surface Tropical cyclones, widespread dust/sand storms, severe squall lines

DEFINITIONS

SIG HI LVL PROG

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SIG LOW LVL PROG CHART Prognostic (forecast) chart that covers altitude range from

Sfc to FL240 (400mb) and contains the following Height of freezing level In flight icing Turbulence Low IFR (less than 500/1) IFR (500/1 to 1000/3)

DEFINITIONS

SIG LOW LVL PROG

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SUMMARY--DEFINITIONS Surface Visibility Prevailing Visibility Tower Visibility RVR AWOS ASOS Inversion

SIGMET AIRMET CWA Weather Watch Weather Warning Sig Low Lvl Prog Sig Hi Lvl Prog

TemperaturePressure

Winds

Free Air Temperature: Actual air temperature also known as: ambient air temp, environmental air temp, real

air temp Cold vs Warm Air: Relative. No set value that makes air cold

or warm Air is cold in an area if surrounding temperatures are warmer Air is warm in an area if surrounding temperatures are colder

TEMPERATURE

Temperature decreases with height through the Troposphere Varies in depth with time, latitude, season

Temperature remains constant through the Tropopause Varies in thickness with time, latitude, season

Temperature increases with height through the Stratosphere

TEMPERATURE

PRESSURE = mass of air in a column of air with its base at a given altitude and the top extending to the top of the atmosphere Pressure is always a maximum at the earth’s surface Pressure always decreases with height Pressure at any altitude is the mass of air in the column

above that altitude

PRESSURE

Station Pressure: actual atmospheric pressure observed at field elevation

Sea Level Pressure: station pressure corrected to sea level using average temperature for last 12 hours

Altimeter Setting: station pressure corrected to sea level using standard temperature lapse rate

PRESSURE

PRESSURE (MB) HEIGHT (FT MSL)

1000 400

850 5000

700 10000

500 18000

400 24000

300 30000

250 34000

200 39000

100 53000

70 63000

PRESSURE AND ALTITUDE

High vs Low Pressure: relative. No set value above or below which makes an area of pressure a high or a low An area of pressure is a low if the surrounding pressure values are higher

also referred to as a “trough” or “trof” An area of pressure is a high if the surrounding pressure values are lower

also referred to as a “ridge” Meteorological terms for low and high are “cyclone” and “anticyclone”

respectively

PRESSURE

Pressure is a function of temperature a change in temperature produces a change in pressure

Cold air moving into a low pressure at a given altitude will lower or decrease the pressure at that altitude

Warm air moving into a high pressure at a given altitude will raise the pressure at that altitude

PRESSURE

Wind is a function of pressure Orientation of pressure pattern determines direction

Counter clockwise around a low or trof in Northern Hemisphere Clockwise around a high or ridge in Northern Hemisphere

Horizontal pressure difference (gradient) determines speed greater the difference the stronger the speed

WIND

Jet: a wind speed of 50 knots or stronger at any altitude Jet Core: the area that contains the maximum wind speed at

any altitude Polar Jet: the northernmost band of maximum wind at the

tropopause Subtropical Jet: the southernmost band of maximum wind at

the tropopause

WINDWIND

Definitions, Concepts and Relationships of Temperature Pressure Wind

Knowledge of meaning and relationships is essential

SUMMARY--TEMPERATURE, PRESSURE, AND WINDS

Atmospheric Moisture and

Clouds

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Three Types of Atmospheric Moisture Solid Liquid

Ordinary Supercooled

Gas (Vapor)

ATMOSPHERIC MOISTURE

Solid Ice Crystals, Snow, Ice Pellets, Hail

Liquid Ordinary

Rain, Drizzle, Fog Super Cooled (Liquid but Temperature below freezing)

Freezing Rain, Freezing Drizzle, Ice Fog Gas (Vapor)

Relative Humidity

ATMOSPHERIC MOISTURE

Supercooled Water: in the liquid state but its actual temperature is below freezing Occurs as result of rapid temperature drop, usually the result of

pressure expansion Freezes instantly upon contact with any object or surface whose

actual temperature is at or below freezing is the source of freezing precipitation as well as aircraft icing

ATMOSPHERIC MOISTURE

Gaseous Water (Vapor) Relative Humidity (RH) one method of indicating amount of water

vapor Defined as actual amount of water vapor in the air divided by the

amount of water vapor the air can hold at a given temperature RH is a function of temperature RH changes with temperature change RH changes with water vapor change

Moist air is less dense (lighter) than dry air

ATMOSPHERIC MOISTURE

Two temperatures associated with water vapor Dew Point: the temperature to which air must be lowered

for condensation (gas to liquid) to occur Wet Bulb: the temperature to which air can be lowered by

evaporating (liquid to gas) water into the air Both used as indicators of water vapor in the air

ATMOSPHERIC MOISTURE

5 Deg C or less difference between air temp and dew point Relative humidity is high At surface: fog dew or frost may form

Risk increases as difference decreases Upper air: condensation may occur (liquid water appearing),

frost (ice) may occur Dew point can be used as estimate of early morning low

temperature

SIGNIFICANCE OF DEW POINT TEMPERATURE

Indicates what air temperature will become if evaporation is taking place If wet bulb is below freezing, ice can form even if air

temperature is above freezing Can play a significant role in aircraft ground icing Dew point temperature can be used as an approximation

of wet bulb

SIGNIFICANCE OF WET BULB TEMPERATURE

Two basic types of clouds Stratiform: smooth bases and tops, comes as a layer or

multiple layers Cumuliform: tall, billowy, not layered

Can become imbedded in stratiform clouds

CLOUDS

Form in stable air Vertical motion is relatively small in magnitude and limited in

vertical extent Size of cloud droplets are relatively small

Contain both ordinary and super-cooled water drops as well as ice crystals

Produce non-showery precipitation Drizzle, Freezing Drizzle Rain, Freezing Rain Snow, Snow Grains, Sleet, Ice Pellets

STRATIFORM CLOUDS

Form in unstable air Vertical motion can be quite strong and extensive in height Size of cloud drops can range from small to extremely large

Contain both ordinary and supercooled water as well as ice crystals and hail

Produce showery precipitation with or without lightning and thunder

Precipitation includes Rain, Snow, Hail

CUMULIFORM CLOUDS

Types of Atmospheric Moisture Dew Point and Wet Bulb Temperatures Stratiform and Cumuliform clouds

SUMMARY--ATMOSPHERIC MOISTURE AND CLOUDS

Thunderstormsand

Avoidance

Basic Types Severe Classification Characteristics of Each Type Avoidance Criteria

THUNDERSTORMSAND AVOIDANCE

TWO BASIC TYPES AIRMASS SQUALL LINE (NON-AIRMASS)

ALL THUNDERSTORMS IMPLY HAIL, SEVERE TO EXTREME TURBULENCE, SEVERE TO

EXTREME CLEAR OR MIXED ICE

THUNDERSTORMS

ANY THUNDERSTORM (AIR MASS OR SQUALL LINE) IS SEVERE IF FORECAST OR ACTUAL SURFACE WIND EQUALS OR EXCEEDS 50

KNOTS FORECAST OR ACTUAL HAIL AT SURFACE EQUALS OR EXCEEDS

3/4 INCH FORECAST OR ACTUAL TORNADO

ABOVE CONDITIONS ARE “AND/OR”

SEVERE THUNDERSTORMS

TRIGGERED BY SURFACE HEATING OR OROGRAPHIC (TERRAIN) LIFTING

USUALLY EXIST AS SINGLE CELL, SOMETIMES AS A LOOSE CLUSTER USUALLY NOT SEVERE AT SURFACE CAN PRESENT SIGNIFICANT HAZARD TO ALL AIRCRAFT IN FLIGHT

AIR MASS THUNDERSTORMS

TRIGGERED BY FRONTS OR TROUGHS (TROFS) CELLS FORM IN LINES ORIENTED PARALLEL TO FRONT OR TROUGH

LINE MOVES IN SAME DIRECTION AS FRONT OR TROUGH CELLS MOVE WITH 500MB (18000FT) WIND AT HALF THE SPEED

TOPS OF CELLS OFTEN EXTEND INTO STRATOSPHERE (OVERSHOOTING)

SQUALL LINE THUNDERSTORMS

LINES AVERAGE 150NM LONG BY 25 TO 50 NM WIDE CELLS ARE FREQUENTLY SEVERE CELLS OFTEN PRODUCE TORNADOS ALWAYS PRODUCE SIGNIFICANT INFLIGHT HAZARDS MUST ABSOLUTELY BE AVOIDED

SQUALL LINE THUNDERSTORMS

SEVERE TO EXTREME TURBULENCE IN CELLS AS WELL AS AROUND OUTSIDE

ANY THUNDERSTORM ACTS AS OBSTRUCTION TO WIND AT ANY ALTITUDE PRODUCES TURBULENCE IN AIR AROUND OUTSIDE OF STORM EXTENT OF TURBULENCE IS A FUNCTION OF WIND SPEED

THUNDERSTORM AVOIDANCE CRITERIA

WINDSPEEDS OF 50KTS OR MORE 20 TO 25 NM FROM EDGE OF CLOUD

WINDSPEEDS OF 30 TO 50 KTS 15 TO 20 NM FROM EDGE OF CLOUD

WINDSPEEDS 30 KTS OR LESS 10 TO 15 NM FROM EDGE OF CLOUD

ABOVE HOLD AT ALL ALTITUDES NEVER FLY UNDER AN “ANVIL”

THUNDERSTORM AVOIDANCE CRITERIA

OVER THE TOPS - MAINTAIN 5000FT OF CLEARANCE FOR ANY WIND SPEED UP TO 50

KTS ADD 1000FT FOR EACH 10 KTS ABOVE 50KTS

60KTS = 6000FT, 70KTS = 7000FT, ETC

THUNDERSTORM AVOIDANCE CRITERIA

Thunderstorms Types Characteristics Avoidance Criteria

SUMMARY--THUNDERSTORMS AND AVOIDANCE

Aircraft Inflight Icing

TWO CONDITIONS VISIBLE MOISTURE (SUPERCOOLED WATER)

ICE CRYSTALS WILL NOT PRODUCE ICING FREE AIR (ACTUAL) TEMPERATURE RANGE BETWEEN 0 AND

MINUS 40 DEGREES C USE “SAT” IF AVAILABLE OTHERWISE, CORRECT INDICATED TO FREE AIR

TEMPERATURE AIR TEMPERATURE OUTSIDE AIRCRAFT PRODUCES ICE

INFLIGHT ICING

HAZARDS CHANGES SHAPE OF AIRFOIL SMALL AMOUNT OF ICE CAN PRODUCE SIGNIFICANT HAZARD

TYPES OF AIRCRAFT ICE RIME CLEAR MIXED

INFLIGHT ICING

RIME ICE OPAQUE OR MILKY IN APPEARANCE ROUGH IN TEXTURE FORMED BY SMALL SUPERCOOLED WATER DROPS FOUND IN STRATIFORM CLOUDS PRIMARILY FORMS ON LEADING EDGES USUALLY LIGHT TO MODERATE IN ACCUMULATION

INFLIGHT ICING

CLEAR ICE CLEAR IN APPEARANCE TAKES SHAPE OF OBJECT/SURFACE FORMING ON FORMED BY LARGE SUPERCOOLED WATER DROPS FOUND IN CUMULIFORM CLOUDS

BASES OF PRECIPITATING STRATIFORM CLOUDS RAIN OR DRIZZLE UNDERNEATH STRATIFORM CLOUDS

(FREEZING RAIN OR FREEZING DRIZZLE)

INFLIGHT ICING

CLEAR ICE FORMS ON ALL SURFACES INCLUDING LEADING EDGES MODERATE OR GREATER IN INTENSITY

FREQUENTLY SEVERE TO EXTREME CLEAR ICE CAN ACCUMULATE RAPIDLY AND IS A MAJOR HAZARD

TO FLIGHT

INFLIGHT ICING

MIXED ICE COMBINATION OF RIME AND CLEAR OCCURING

SIMULTANEOUSLY CLEAR AND OPAQUE IN APPEARANCE ROUGH IN TEXTURE FOUND IN CUMULIFORM IMBEDED IN STRATIFORM CLOUDS

LOWER PORTION OF PRECIPITATING STRATIFORM CLOUDS

INFLIGHT ICING

MIXED ICE MODERATE OR GREATER IN ACCUMULATION

FREQUENTLY SEVERE TO EXTREME MIXED ICE CAN RAPIDLY ACCUMULATE AND IS A MAJOR FLIGHT

HAZARD

INFLIGHT ICING

ICING FORECAST PRODUCTS AREA FORECASTS (FAs) SIGMETs AIRMETs ICING FORECAST CHART (MAP) SIG LOW LEVEL PROG CHART (MAP)

INFLIGHT ICING

CONDITIONS FOR FORMATION TYPES OF INFLIGHT ICING ICING FORECAST PRODUCTS

SUMMARY--INFLIGHT ICING

Ground Icing

HAZARDS FORMATION RECOGNITION CHARACTERISTICS OF DEICING AND ANTI ICING FLUIDS HOLDOVER CHARTS AND TIMES COMMUNICATIONS PRE DEPARTURE ICING CHECK

GROUND ICING

CHANGES SHAPE OF AIRFOIL CAN SERIOUSLY DEGRADE TAKEOFF PERFORMANCE CAN SIGNIFICANTLY CHANGE STALL SPEED

AFFECTS CONTROLABILITY CHANGES CRITICAL/EFFECTIVE AOA OF MAIN WING AND

HORIZONTAL STABILIZER

GROUND ICING HAZARDS

SMALL AMOUNT OF FROZEN OR PARTLY FROZEN MATERIAL IS SIGNIFICANT HAZARD

CAN FORM IN SITUATION THAT DOES NOT OBVIOUSLY APPEAR FAVORABLE FOR FORMATION OF ICE

GROUND ICING HAZARDS

FACTORS Melting/Refreezing Precipitation Wind speed Air temperature Wet bulb temperature Dew point temperature Evaporative cooling Expansion cooling

FORMATION OF GROUND ICE

EVAPORATIVE COOLING Cooling of air and exposed surfaces to wet bulb temperature

through evaporation Aided by wind speed of 10kts or more Ice, Slush can form if wet bulb temperature is below freezing

Use dew point temperature as approximate wet bulb CREATES VERY DANGEROUS SITUATION IF AIR TEMP ABOVE

FREEZING

FORMATION OF GROUND ICE

EXPANSION COOLING Cooling of air as result of rapid pressure drop (expansion) Rapid pressure drop (expansion) occurs over top of airfoils

SLUSH OR SOFT ICE CAN FREEZE ON AIRFOIL DURING TAKEOFF

FORMATION OF GROUND ICE

CONCLUSION GROUND ICE CAN FORM WHEN AIR TEMPERATURE IS BELOW

FREEZING EVAPORATIVE COOLING CAN FORM GROUND ICE ON AIRCRAFT

WHEN AIR TEMPERATURE IS ABOVE FREEZING USE DEW POINT TEMPERATURE AS INDICATOR OF ICING

POTENTIAL

FORMATION OF GROUND ICE

CHARACTERISITCS OF DEICING - ANTI ICING FLUIDS

GROUND ICING

GLYCOL BASED Ethlyne Diethlyne Propelyne

LOWER THE FREEZING POINT OF WATER SOLUABLE IN WATER

Lower the freezing point of water Dilution by water raises freezing point of solution

DEICING - ANTI ICING FLUIDS

SAME FLUID CAN BE USED FOR BOTH: Deicing (removal of ice, frost, slush) Anti Icing (prevent formation of ice, frost, slush)

FLUIDS CAN BE: Heated

Prefered for Deicing Not Heated

Prefered for Anti Icing

DEICING - ANTI ICING FLUIDS

FLUID VISCOSITY IS SIGNIFICANT TO BEHAVIOR OF FLUID VISCOSITY IS:

Relative Thickness or Thiness of fluid HIGH VISCOSITY FLUID

Thick Holds its own shape Examples: honey, syrup, heavy oil

DEICING - ANTI ICING FLUIDS

LOW VISCOSITY FLUID Thin Will not hold its own shape Example: water, etc

VISCOSITY DETERMINES BEHAVIOR AND EFFECTIVENESS OF ANTI ICING FLUID

DEICING - ANTI ICING FLUIDS

LOW VISCOSITY (THIN) FLUID WILL Shear Off (Blow Off) as soon as any shearing force (moving

air) occurs Wind, Jet Exhaust, Taxiing, Take Off

Known as Newtonian fluid Will not be contaminant Provide a short protection time against formation of ice

DEICING - ANTI ICING FLUIDS

HIGH VISCOSITY (THICK) FLUID WILL Shear off (Blow Off) only when specific shearing force (moving

air) occurs Known as a Non -Newtonian fluid

Means the moving air must reach a certain speed before it will move fluid

Required speed is determined by actual viscosity of fluid Can be a “contaminant” Provide a longer protection time against formation of ice

DEICING - ANTI ICING FLUIDS

TWO TYPES OF ANTI ICING FLUID AVAILABLE TYPE I

Low Viscosity Thin

TYPE II High Viscosity Thick

TYPE OF FLUID DETERMINES HOLDOVER TIME

DEICING - ANTI ICING FLUIDS

HOLDOVER TIMES & CHARTSHOLDOVER TIMES & CHARTS

GROUND ICING

HOLDOVER TIME Period of time that Anti Icing fluid will be effective Determined by

Type of Fluid Fluid and Water Mix Precipitation Type and Intensity Air Temperature

BEGINS AT START OF SPRAY

HOLDOVER TIME & CHARTS

DANGEROUS SCENARIO IF: Precipitation occurring (any type) Wind speed is 10 knots or more Air temperature above freezing Dew point below Freezing

USE DEW POINT FOR TEMPERATURE VALUE ON HOLDOVER CHART Will account for evaporative cooling

HOLDOVER TIME

COMMUNICATIONS

GROUND ICING

NEED TO KNOW: Weather conditions

type & intensity of precipitation wind air temperature dew point temperature

Type of Deicing - Anti icing fluid fluid concentration

Time fluid spraying began

COMMUNICATIONS

REQUIRED TO ACCOMPLISH PRE TAKEOFF CONTAMINATION CHECK WITHIN 5 MINUTES OF DEPARTURE MAY BE DONE FROM INSIDE OR OUTSIDE AIRCRAFT

FOR PREVIOUS DANGEROUS SCENARIO RECOMMEND CHECK BE DONE OUTSIDE PHYSICALLY TOUCH SURFACES TO DETERMINE IF ICE HAS

FORMED

FINAL STEP

Factors involved Fluids and Characteristics Holdover Charts and Times Communications Requirements Pre Takeoff Contamination Check

GROUND ICING--SUMMARY

Low Level Windshear

What It Is How It Affects an Aircraft Examples Weather Conditions to Watch For Rules of Thumb

LOW LEVEL WINDSHEAR

Low Level first 2000 feet above the ground

High Level more than 2000 feet above the ground

Why the distinction force of friction

Friction affects wind in bottom 2000 feet does not affect it above 2000 feet

WHAT IS LOW LEVEL?(Meteorologically Speaking)

“Low Level Windshear” Windshear from the sfc to 2000 feet agl

“High Level Windshear” Turbulence

LOW LEVEL vs HIGH LEVEL

WINDSHEAR IS TURBULENCE NO MATTER WHERE IT OCCURS

A rapid change in the speed and or direction of the wind in a small distance either in the horizontal or vertical or both

Definition of Windshear

A rapid change in the speed and or direction of the wind in a small distance either in the horizontal or vertical or both

Definition of Windshear

HORIZONTAL Wind flow parallel to ground at any altitude and any geographic

location Simply wind direction and speed on takeoff, climb, , enroute

descent, landing

WIND COMPONENTS

VERTICAL Wind perpendicular to the ground Upward and downward motion Occurs at same points as horizontal

WIND COMPONENTS

HORIZONTAL Only one significant 80 to 85% of time Vertical too small to affect aircraft (100 fpm is lowest

value) Specific weather events that produce only horizontal

shear

HORIZONTAL/VERTICAL

VERTICAL Strong as 13,000fpm or more Average is 2500 - 3000fpm 100 to 500fpm to cause problem Specific wx events that produce only vertical shear

HORIZONTAL/VERTICAL

When Significant Vertical Motion Present, Significant Horizontal Is Also Present

TWO FOR THE PRICE OF ONE

HORIZONTAL Only One Significant 80 to 85% of Time

VERTICAL Significant Only 15 to 20% of Time Produces Significant Horizontal

COMBINED Both Horizontal and Vertical

SUMMARY-- WIND COMPONENT

A rapid change in the speed and or direction of the wind in a small distance either in the horizontal or vertical or both

DEFINITION OF WINDSHEAR

RAPID CHANGE - 15 to 120 seconds SMALL DISTANCE - hundred feet to 5nm TIME RANGE 15 TO 120 SECONDS

Means wind can change direction or speed INSTANTANEOUSLY over a time period of 15 to 120 seconds

HUNDRED FEET TO 5NM Means wind can change direction or speed INSTANTANEOUSLY at

any point or points a hundred feet apart over distance of 5nm

RAPID CHANGE/SMALL DISTANCE

WINDSHEAR AFFECTS AN AIRCRAFT’S LIFT BECAUSE THE WIND CHANGES THE LIFT FASTER THAN THE AIRCRAFT’S MASS CAN BE ACCELERATED OR DECELERATED TO COMPENSATE FOR THE CHANGE

EFFECTS ON AIRCRAFT

INSTANTANEOUS CHANGES IN WIND SPEED OR DIRECTION PRODUCE INSTANTANEOUS CHANGES IN AIRSPEED AND LIFT

REACTION TO CHANGE TAKES 12 TO 15 SECONDS AND INCLUDES: PILOT’S REACTION ( 2.5 TO 3.8 SECONDS) AIRCRAFTS RESPONSE TIME TO COMMANDS

--VARIES CONSIDERABLY BY TYPE

HOW IT DOES IT!

PRIMARY CULPRIT HORIZONTAL WIND COMPONENT

ASSISTANT OR CONFUSER VERTICAL WIND COMPONENT CAN DO IT BY ITSELF!!

MOST DANGEROUS CASE SIMULTANEOUS HORIZONTAL & VERTICAL

LOW LEVEL WINDSHEAR

FROM ONE POINT TO ANOTHER AT A CONSTANT ALTITUDE

ON A DESCENT OR CLIMB

CHANGE IN HORIZONTAL COMPONENT

COMBINED WIND CONVECTIVE WX

SHOWERS RAIN, SNOW, VIRGA

THUNDERSHOWERS RAIN, SNOW, VIRGA

MOUNTAIN WAVE ROTORS

LOW LEVEL WINDSHEAR WEATHER EVENTS

HORIZONTAL WIND FRONTS

WARM COLD

SEA BREEZES VALLEY WINDS TEMP INVERSIONS

LOW LEVEL WINDSHEAR WEATHER EVENTS

CONVECTIVE WEATHER PRESENCE OF CB’s OR TCU’s VIRGA PRECIPITATION SHAFT BLOWING DUST BENDING TREES GUSTY SURFACE WINDS

THINGS TO WATCH FOR!

MOUNTAIN WAVE COPIOUS HIGH ALTITUDE TURBULENCE ON LEE SIDE ROTOR CLOUD REMARKS IN METAR STANDING LENTICULAR CLOUD REMARKS IN METAR

BLOWING DUST ERRATIC GUSTY SURFACE WINDS (no apparent cause) LARGE TEMP - DEW POINT DIFFERENCE

THINGS TO WATCH FOR!

FRONTS WARM FRONT

AIRPORT WITHIN 125NM ON COOL SIDE OF BOUNDARY COLD FRONT

AIRPORT WITH 15NM ON COOL SIDE OF BOUNDARY

THINGS TO WATCH FOR!

TEMPERATURE INVERSION CALM SURFACE WIND COOL, EARLY MORNING TEMPERATURES CLEAR SKIES (OVERNIGHT OR EARLY MORNING)

SEA BREEZE CU ALONG COAST INDICATIONS OF ONSHORE FLOW

VALLEY WINDS GUSTY SURFACE WINDS BLOWING DUST

THINGS TO WATCH FOR!

THE AIRCRAFT IN FRONT OF YOU THAT RESPONDS WHEN ASKED, “HOW WAS THE RIDE UNDER THAT BLACK CLOUD?”

WATCH OUT FOR!

IT DOSEN’T LOOK THAT BAD! OH WELL, THAT’S ROUTINE WX FOR THIS PLACE! IT’S A TYPICAL COLORADO WINDY DAY! DOSEN’T SEEM TO BE BOTHERING ANYONE ELSE! THERE ARE ALWAYS SHOWERS AROUND THIS PLACE!

FAMOUS LAST WORDS

CONVECTIVE WEATHER DOUBLE THE GUST SPEED ADD THE FULL PREVAILING TO THE FULL GUST

EXAMPLE: 15G25 = 40 TO 50 KNOT LOSS MULTIPLY THE FULL GUST SPEED BY 100 AND LABEL IT “FPM”

EXAMPLE: 25 X 100 = 2500 FEET PER MINUTE DOWNDRAFT

YES! ROUTINE SHOWERS ARE KILLERS!!!

RULES OF THUMB

NON CONVECTIVE WEATHER DIFFERENCE BETWEEN NAV EQUIPMENT WIND AT 1000 FEET

AND SFC WIND DIRECTION AND SPEED WILL OCCUR WITHIN 50 TO 100 FEET ABOVE HEIGHT OF

AVERAGE OBSTRUCTION AROUND AIRPORT WILL OCCUR AT BASE OF REPORTED CEILING IN FRONTAL CASES WILL OCCUR BY 200 TO 300 FT AGL IN OTHERS

RULES OF THUMB

GUSTY SURFACE WINDS (NON CONVECTIVE) DETERMINE THE DIFFERENCE BETWEEN PREVAILING SPEED

AND THE “FULL” GUST EXAMPLE: 13G30 = 17KT POTENTIAL LOSS

RULES OF THUMB

AVOID IT!!

CONVECTIVE WX STAY OUT OF PRECIPITATION SHAFT STAY OUT OF VERTICAL SPACE FROM THE CLOUD BASE TO THE GROUND STAY 5 NM FROM EDGE OF CLOUD

HOW TO HANDLE LOW LEVEL WINDSHEAR

IN GENERAL AIRSPEED FLUCTUATION OF 5 TO 10 KNOTS

GET READY AIRSPEED FLUCTUATION OF 10 TO 15 KNOTS

GET SET AIRSPEED FLUCTUATION 15 KNOTS OR MORE

LETS GO AROUND AND EVALUATE THE SITUATION!

HOW TO HANDLE LOW LEVEL WINDSHEAR

PAY ATTENTION TO THE WEATHER! DON’T GET CAUGHT! KEEP IT SAFE!

REMEMBER: YOU MAY BE ABLE TO HANDLE IT, BUT THE AIRCRAFT YOU ARE FIRMLY ATTACHED TO MAY NOT BE ABLE TO HANDLE IT!

SUMMMARY--WINDSHEAR

Oral, written examination not required

Examination

Student Fill-out Student Feedback Form Sign Training Record (if applicable)

Instructor Sign Class Roster Fill-out Instructor Feedback Form Sign Training Record (if applicable)

Completion of Paperwork