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Understanding Aircraft Understanding Aircraft IcingIcing
Nick CzernkovichNick Czernkovich
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““Aircraft Icing”Aircraft Icing”
Aircraft icing can be broken down Aircraft icing can be broken down into 2 categories:into 2 categories:
Induction System IcingInduction System Icing Structural IcingStructural Icing
Structural Icing
Ground Icing In-Flight Icing
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Some General StatisticsSome General Statistics
10.8 %10.8 % of all weather accidents of all weather accidents result from icingresult from icing
3 leading factors:3 leading factors: 51.2 %51.2 % - Carburetor icing - Carburetor icing 41.4 %41.4 % - In-Flight icing - In-Flight icing 7.7 %7.7 % - Ground Icing - Ground Icing
PIC average flight time: PIC average flight time: 1,964 hrs1,964 hrs Average time on type: Average time on type: 306 hrs306 hrs Percent Instrument Rated: Percent Instrument Rated: 71 %71 %
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In-Flight Icing StatisticsIn-Flight Icing Statistics
Cause of approximately Cause of approximately 30 fatalities30 fatalities and and 14 injuries14 injuries per year in U.S. per year in U.S.
Result of US Result of US $96 million$96 million per year in per year in personal injury and damagepersonal injury and damage
Between 1978 and 1989, contributed to Between 1978 and 1989, contributed to 298 fatalities298 fatalities in Canada in Canada
In In 57%57% of icing accidents pilots had of icing accidents pilots had received an icing forecastreceived an icing forecast
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Pilot Awareness About IcingPilot Awareness About Icing
One study concluded the following:One study concluded the following:• “…“…pilots do not understand the combined pilots do not understand the combined
meteorological and aircraft conditions that meteorological and aircraft conditions that cause structural ice…”cause structural ice…”
• ““[Pilots] have a poor understanding of the [Pilots] have a poor understanding of the concept of collection efficiency that causes concept of collection efficiency that causes smaller parts of the airplane…to collect more smaller parts of the airplane…to collect more ice than larger parts.”ice than larger parts.”
• ““All of the pilots surveyed have a very poor All of the pilots surveyed have a very poor understanding of the specific effects ice has on understanding of the specific effects ice has on the aerodynamics of the aircraft.”the aerodynamics of the aircraft.”
(COMET Baseline Needs Assessment)(COMET Baseline Needs Assessment)
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OUTLINEOUTLINE
1.1. Past Studies and Current ResearchPast Studies and Current Research
2.2. Physics of Icing EnvironmentsPhysics of Icing Environments
3.3. Icing Certification and SLDIcing Certification and SLD
4.4. Dynamics of IcingDynamics of Icing
5.5. Flight PlanningFlight Planning
6.6. In-Flight StrategiesIn-Flight Strategies7.7. NASA Icing Video NASA Icing Video (Control Anomalies)(Control Anomalies)
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Past Studies and Current Past Studies and Current ResearchResearch
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Recent MotivationRecent Motivation
October 1994 crash of an ATR-72 near October 1994 crash of an ATR-72 near Roselawn, IndianaRoselawn, Indiana
1995, 1996/1997, 1997/1998, 1999/2000 – 1995, 1996/1997, 1997/1998, 1999/2000 – CFDE I/II/III and AIRS (respectively)CFDE I/II/III and AIRS (respectively)
AIRS – AIRS – Improve ability to remotely sense icing regionsImprove ability to remotely sense icing regions Better characterize icing environmentsBetter characterize icing environments Improve ability to forecast icing conditionsImprove ability to forecast icing conditions Obtain measurements of aircraft performance in icing Obtain measurements of aircraft performance in icing
conditionsconditions
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Some of the tools…Some of the tools…
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McGill Vertically Pointing RadarMcGill Vertically Pointing Radar
The VPR
VPR Data output:
Reflectivity in dBZ
Velocity in m/s
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Physics of IcingPhysics of Icing
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Physical States (Phases)Physical States (Phases)
Three physical states: Three physical states: • SolidSolid• LiquidLiquid• VapourVapour
Water can exist in the atmosphere in all Water can exist in the atmosphere in all three phasesthree phases
Transition between phases takes place all Transition between phases takes place all the time, results in “Weather”the time, results in “Weather”
Phase changes consume/release Phase changes consume/release latent heatlatent heat
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Phase ChangesPhase Changes
CondensationCondensation EvaporationEvaporation FreezingFreezing MeltingMelting SublimationSublimation DepositionDeposition
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Two Points to RememberTwo Points to Remember
Ice will always melt at 0 C, but liquid Ice will always melt at 0 C, but liquid water water will notwill not necessarily freeze at 0 C necessarily freeze at 0 C
Evaporation, sublimation and Evaporation, sublimation and deposition need not occur at any deposition need not occur at any specific temperaturespecific temperature
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Formation of CloudsFormation of Clouds
Clouds are Clouds are visible moisturevisible moisture Can be composed of Can be composed of liquid dropletsliquid droplets
or or ice crystalsice crystals Generally form as a result of air Generally form as a result of air
being lifted and cooledbeing lifted and cooled
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A Note on HumidityA Note on Humidity
Relative Humidity = % saturationRelative Humidity = % saturation Temperature – Dew Point spread is a Temperature – Dew Point spread is a
measure of RHmeasure of RH Smaller T-Td spread = Higher RHSmaller T-Td spread = Higher RH
Ok so far?Ok so far?Airmass #1 has Airmass #1 has T=20CT=20C and and Td=5CTd=5CAirmass #2 has Airmass #2 has T=8CT=8C and and Td=5CTd=5CWhich has a higher RH?Which has a higher RH?Which contains more water vapour?Which contains more water vapour?
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A Note on HumidityA Note on Humidity
Airmass #2Airmass #2 has a higher RH because has a higher RH because the T-Td spread is smallerthe T-Td spread is smaller
They both hold the They both hold the same amount of same amount of water vapourwater vapour
Temperature puts a cap on dew point Temperature puts a cap on dew point because because T >= TdT >= Td, ALWAYS, ALWAYS
TdTd is a measure of water vapour is a measure of water vapour available, available, not Tnot T
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Warm Cloud ProcessWarm Cloud Process
Definition: Entire depth of cloud is Definition: Entire depth of cloud is above 0 Cabove 0 C
Expect to find only liquid dropletsExpect to find only liquid droplets Often forms due to:Often forms due to:
• Frontal liftingFrontal lifting• Orographic LiftingOrographic Lifting• BuoyancyBuoyancy• ConvergenceConvergence• TurbulenceTurbulence
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Warm Cloud ProcessWarm Cloud Process
Lifting Condensation Level
RH = 100%
Rising air expands and
cools
Amount of Moisture in parcel remains constant
Water begins to condense
Phase change Vapour Liquid
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Warm Cloud Process:Warm Cloud Process:Formation of Cloud DropletsFormation of Cloud Droplets
Homogeneous Homogeneous NucleationNucleation not not observedobserved
Heterogeneous Heterogeneous
NucleationNucleation•Vapour condenses Vapour condenses onto tiny particles onto tiny particles called CCNcalled CCN•CCN are CCN are always always abundantabundant in the in the atmosphereatmosphere
Typical cloud droplet size ~10 to 20 microns
1 micron = 1/1000 mm
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Warm Cloud Process:Warm Cloud Process:Cloud Droplets to RainCloud Droplets to Rain
Drops grow by Drops grow by condensation up to condensation up to 20 microns20 microns
After 20 microns After 20 microns collision-coalescencecollision-coalescence dominatesdominates
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Warm Cloud Process:Warm Cloud Process:SummarySummary
Clouds develop as air is Clouds develop as air is lifted to saturationlifted to saturation CCNCCN become activated become activated Cloud droplets grow by condensation up to Cloud droplets grow by condensation up to
about about 20 microns20 microns After 20 microns After 20 microns collision-coalescencecollision-coalescence
dominatesdominates When fall speeds of drops exceed updraft When fall speeds of drops exceed updraft
speed in cloud speed in cloud Precipitation Precipitation
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Cold CloudsCold Clouds
Definition: Some or all of the cloud is Definition: Some or all of the cloud is at or below 0 Cat or below 0 C
Formed through the same process as Formed through the same process as warm cloudswarm clouds
PossibilityPossibility of forming ice particles of forming ice particles Ice particles Ice particles mustmust form onto aerosols form onto aerosols
called called Freezing NucleiFreezing Nuclei ( (FNFN))
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Cold CloudsCold CloudsReality of Freezing NucleiReality of Freezing Nuclei
Liquid drops being Liquid drops being carried above the carried above the freezing level freezing level Drops must contact Drops must contact an FN to freezean FN to freeze
Direct Direct depositiondeposition (vapour(vapourice) ice) requires presence requires presence of FNof FN
If no FN present If no FN present liquid droplets form liquid droplets form on CCNon CCN
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Cold CloudsCold CloudsSome points…Some points…
FN are FN are functions of temperaturefunctions of temperature FN become more important as FN become more important as T< T<
-15C-15C CCT < -15C can glaciate cloud from CCT < -15C can glaciate cloud from
top down (top down (BUT DON’T EXPECT THISBUT DON’T EXPECT THIS)) Ice and Liquid can co-existIce and Liquid can co-exist in in
equilibrium equilibrium Liquid water is possible down to Liquid water is possible down to –40C–40C
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Inferring Icing Conditions From Inferring Icing Conditions From Precipitation ObservationsPrecipitation Observations
Snow (SN)Snow (SN) Graupel/Snow Pellets (GS)Graupel/Snow Pellets (GS) Freezing Rain (FZRA)Freezing Rain (FZRA) Ice Pellets (PL)Ice Pellets (PL) Freezing Drizzle (FZDZ)Freezing Drizzle (FZDZ)
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Inferring Icing ConditionsInferring Icing ConditionsSnow: What you can inferSnow: What you can infer
Likelihood of icing in lowest Likelihood of icing in lowest layer layer reducedreduced
Liquid Cloud layers above the Liquid Cloud layers above the ice are ice are unlikelyunlikely
BUT…Rimed snow suggests BUT…Rimed snow suggests SLW aloftSLW aloft
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Inferring Icing ConditionsInferring Icing ConditionsSnow: What you Snow: What you CANNOTCANNOT infer infer
Only ice exists aloftOnly ice exists aloft No SLW exists aloftNo SLW exists aloft Small amount of SLW Small amount of SLW
existexist
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Inferring Icing ConditionsInferring Icing ConditionsGraupel: What you can inferGraupel: What you can infer
Formed when Formed when snowflakes become snowflakes become heavily rimedheavily rimed
Significant SLWSignificant SLW exists exists aloftaloft
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Inferring Icing ConditionsInferring Icing ConditionsFreezing Rain: What you can inferFreezing Rain: What you can infer
Could be formed by Could be formed by classicalclassical or or non-classical non-classical mechanismmechanism
Freezing rain exists Freezing rain exists from the surface up to from the surface up to some levelsome level
Dangerous icing Dangerous icing conditions likely existconditions likely exist
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Inferring Icing ConditionsInferring Icing ConditionsFreezing Rain: What you Freezing Rain: What you CANNOTCANNOT infer infer
A warm layer exists A warm layer exists aloftaloft
Freezing rain layer is Freezing rain layer is relatively shallowrelatively shallow
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Inferring Icing ConditionsInferring Icing ConditionsIce Pellets: What you can inferIce Pellets: What you can infer
A layer of A layer of freezing rainfreezing rain or or drizzledrizzle exists at exists at some level aloftsome level aloft
If a melting layer If a melting layer exists it is likely to be exists it is likely to be shallowshallow
SLW formed through SLW formed through collision-coalescencecollision-coalescence can also existcan also exist
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Inferring Icing ConditionsInferring Icing ConditionsIce Pellets: What you Ice Pellets: What you CANNOTCANNOT infer infer
A warm layer exists A warm layer exists aloftaloft
Freezing rain/drizzle Freezing rain/drizzle layer is relatively layer is relatively shallowshallow
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Inferring Icing ConditionsInferring Icing ConditionsFreezing Drizzle: What you can inferFreezing Drizzle: What you can infer
Could be formed by Could be formed by classicalclassical or or non-classical non-classical mechanismmechanism
Freezing drizzle exists Freezing drizzle exists from the surface up to from the surface up to some levelsome level
Collision-coalescenceCollision-coalescence more likelymore likely
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Observed Properties of CloudsObserved Properties of CloudsCumulusCumulus
Less likely in winter than in summer Less likely in winter than in summer (but are still observed)(but are still observed)
LWC ~ LWC ~ 0.10.1 toto 3.0 g/m3.0 g/m33
Droplets tend to be largerDroplets tend to be larger than in than in stratusstratus
Vertical extent ~ Vertical extent ~ several kmseveral km Horizontal extent ~ Horizontal extent ~ 5 km5 km toto 10 km10 km Average lifecycle ~ Average lifecycle ~ 30 min30 min toto 1 hr1 hr
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Observed Properties of CloudsObserved Properties of CloudsStratusStratus
More common than cumulus in winterMore common than cumulus in winter LWC ~ LWC ~ 0.1 to 0.8 g/m0.1 to 0.8 g/m33
Droplet sizes tend to be smaller than Droplet sizes tend to be smaller than cumulus (NOT ALWAYS THOUGH!)cumulus (NOT ALWAYS THOUGH!)
Vertical extent usually Vertical extent usually 3000 ft or less3000 ft or less Horizontal extent ~ Horizontal extent ~ several hundred kmseveral hundred km Highest LWC and largest drops usually at Highest LWC and largest drops usually at
cloud topcloud top
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Icing in Cloud: ProbabilityIcing in Cloud: Probability
• 40 %40 % chance of chance of encountering icing in encountering icing in cloud below cloud below 0 C0 C
• 14 %14 % chance of chance of encountering icing in encountering icing in cloud cloud below –20 Cbelow –20 C
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Icing in Cloud: What to ExpectIcing in Cloud: What to Expect
• 90 % of layered clouds have vertical extents of 3000 ft or less
• 90 % of icing encounters last 50 sm or less
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17.4 nm
Certification Into Known IcingCertification Into Known Icing
Meteorological Conditions Specified inMeteorological Conditions Specified in• Canada Canada : : CAR 523/525 Appendix CCAR 523/525 Appendix C• United States: United States: FAR 23/25 Appendix CFAR 23/25 Appendix C
2.6 nm
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Icing Certification: The RealityIcing Certification: The Reality
Drop sizes much Drop sizes much larger than 50 micronslarger than 50 microns have have been found to existbeen found to exist
These are called These are called Supercooled Large Droplets Supercooled Large Droplets (SLD)(SLD)
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Dynamics of IcingDynamics of Icing
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Total Air Temperature vs Total Air Temperature vs Static Air TemperatureStatic Air Temperature
TATTAT = = SATSAT + + Kinetic EffectsKinetic Effects Temperature at stagnation point will be Temperature at stagnation point will be
higher than SAT due to local pressure higher than SAT due to local pressure increaseincrease
Temperature can vary across wing surfaceTemperature can vary across wing surface
One Example:One Example:• Standard AirfoilStandard Airfoil• 150 kts TAS150 kts TAS• 1.9 C drop across airfoil1.9 C drop across airfoil
THE POINTTHE POINT
Icing can occur even whenIcing can occur even when
temperatures are above 0 C!temperatures are above 0 C!
(Up to ~ +4 C)(Up to ~ +4 C)
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Types of IcingTypes of Icing
Clear (Glaze)Clear (Glaze) RimeRime MixedMixed
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Types of Icing: Types of Icing: Clear IceClear Ice Temperatures (Temperatures (rule of thumbrule of thumb) ) 0 C to –10 C0 C to –10 C Often the result of Often the result of larger dropletslarger droplets
Droplet impinging on airfoil Droplet impinging on airfoil does not freeze does not freeze instantlyinstantly
Latent Heat releaseLatent Heat release + + Kinetic Temperature Kinetic Temperature cause cause part of the droplet to runbackpart of the droplet to runback
Accumulations can form protrusions that can Accumulations can form protrusions that can dramaticallydramatically reduce liftreduce lift + + increase dragincrease drag
Can be Can be difficult to detectdifficult to detect (especially at night) (especially at night)
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Types of Icing: Types of Icing: Rime IceRime Ice
Temperatures Temperatures • Possibility Possibility 0 C to –40 C0 C to –40 C• Rule of Thumb Rule of Thumb –15 C to –40 C–15 C to –40 C
Droplets usually smallerDroplets usually smaller
Droplets Droplets freeze on impactfreeze on impact Air becomes trapped between frozen Air becomes trapped between frozen
dropletsdroplets Milky whiteMilky white in appearance in appearance Generally Generally conforms to leading edgeconforms to leading edge
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Types of Icing: Types of Icing: MixedMixed
Temperatures (rule of thumb) Temperatures (rule of thumb) ––10 C to –15 C10 C to –15 C
Encompasses a continuum between Rime Encompasses a continuum between Rime and Clearand Clear
Can form Can form protrusionsprotrusions like Clear Ice but like Clear Ice but more white in colourmore white in colour
Should be treated with the same level of Should be treated with the same level of cautioncaution
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Wind Tunnel Tests on a CylinderWind Tunnel Tests on a Cylinder
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Some PicturesSome Pictures
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Icing TypesIcing TypesSummarySummary
General Observations:General Observations:• Clear Clear 0 C to –10 C0 C to –10 C• Mixed Mixed –10 to –15 C–10 to –15 C• Rime Rime –15 C to –20 C–15 C to –20 C
TypicallyTypically::• RimeRime – – StratiformStratiform• ClearClear – – CumuliformCumuliform
TemperatureTemperature + + Drop SizeDrop Size Icing TypeIcing Type LWCLWC + + Drop SizeDrop Size Accretion Rate Accretion Rate AirspeedAirspeed also a factor (Kinetic Heating) also a factor (Kinetic Heating)
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Dynamics of IcingDynamics of Icing Collection Efficiency of an objectCollection Efficiency of an object
Droplet SizeDroplet Size Object ShapeObject Shape AirspeedAirspeed
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Dynamics of IcingDynamics of IcingAccretionAccretion
LWCLWC most significantmost significant parameter in parameter in determining ice accretion ratedetermining ice accretion rate
Duration of exposureDuration of exposure Total accretionTotal accretion
Drop SizeDrop Size SecondarySecondary(Although is a significant factor)(Although is a significant factor)
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Dynamics of IcingDynamics of IcingDangers of Ice Outside CAR 525-CDangers of Ice Outside CAR 525-C
Large Droplets:Large Droplets:• Ice aft of Ice aft of
protected surfaceprotected surface• RidgingRidging
High LWCHigh LWC• RunbackRunback• RidgingRidging
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Performance PenaltiesPerformance Penalties
Decreased LiftDecreased Lift Increased DragIncreased Drag Decreased Stall Decreased Stall
AngleAngle Increased Stall Increased Stall
SpeedSpeed
Increased VibrationIncreased Vibration Changes in Changes in
Pressure Pressure DistributionDistribution
Early Boundary Early Boundary Layer SeparationLayer Separation
Reduced Reduced ControllabilityControllability
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Performance PenaltiesPerformance Penalties
Studies have shownStudies have shown• Drag increaseDrag increase up to up to 40 %40 % or more or more• Lift decreaseLift decrease up to up to 30 %30 % or more or more• Stall speed increaseStall speed increase of of 15 to 20 %15 to 20 %
(Even with a very small coating of ice)(Even with a very small coating of ice)
• Propeller efficiencyPropeller efficiency decrease of decrease of 19 %19 %
• One incident during research:One incident during research: 36 % drag increase36 % drag increase resulting from ice on resulting from ice on unprotected unprotected
surfacessurfaces, after boots were cycled, after boots were cycled
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Whenever you encounter Whenever you encounter ice, you should always ice, you should always
start working to get outstart working to get out
Remember this…Remember this…
CAR 525-C Based on:CAR 525-C Based on:• 17.4 nm17.4 nm in continuous maximum icing in continuous maximum icing• 2.6 nm2.6 nm in intermittent maximum icing in intermittent maximum icing• Droplets up to Droplets up to 50 micorns50 micorns
Ice on unprotected surfaces caused a Ice on unprotected surfaces caused a 36 % increase in drag36 % increase in drag
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Icing SeverityIcing Severity
TraceTrace – Ice protection equipment may be – Ice protection equipment may be required for flight in icing longer than 1 hourrequired for flight in icing longer than 1 hour
LightLight – Ice protection equipment is required – Ice protection equipment is required for flight in icing for about 1 hourfor flight in icing for about 1 hour
ModerateModerate – Ice protection equipment is – Ice protection equipment is required for flight in icing for even short required for flight in icing for even short periods of timeperiods of time
SevereSevere – Rate of accumulation is so severe – Rate of accumulation is so severe that ice protection equipment fails to reduce that ice protection equipment fails to reduce or control the hazardor control the hazard
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Flight PlanningFlight Planning
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Checking the WeatherChecking the WeatherRemember the Physics of IcingRemember the Physics of Icing
ClimatologyClimatology• 53 %53 % - near - near
mountainous terrainmountainous terrain• 14 %14 % - near large - near large
bodies of waterbodies of water• 33 %33 % - other - other
95 % of accidents occur 95 % of accidents occur during during approachapproach, , landinglanding, , holdingholding and and go-go-aroundaround
Forecasting Rule #1Forecasting Rule #1• Know your terrain!Know your terrain!
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Checking the WeatherChecking the WeatherGet the “BIG” PictureGet the “BIG” Picture
Review Surface AnalysisReview Surface Analysis• Low Pressure Areas (Cyclones)Low Pressure Areas (Cyclones)• Fronts (Warm/Cold/Occluded)Fronts (Warm/Cold/Occluded)• Observe winds, look for areas of lift Observe winds, look for areas of lift
(Fronts,Terrain,Convergence,etc..)(Fronts,Terrain,Convergence,etc..)
Review the Upper Air ChartsReview the Upper Air Charts
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Checking the WeatherChecking the WeatherFrontsFronts
Check surface and Check surface and upper air stations for upper air stations for airflowairflow• Warm Conveyor BeltWarm Conveyor Belt• Cold Conveyor BeltCold Conveyor Belt
Check source of airflowCheck source of airflow (warm & moist flow over (warm & moist flow over cold arctic air cold arctic air Good Good chance of Freezing chance of Freezing PrecipitationPrecipitation
Max precipitationMax precipitation usually usually W/NW quadrantW/NW quadrant
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Checking the WeatherChecking the WeatherFrontsFronts
Warm FrontsWarm Fronts • 1:2001:200• Icing up to +300 nm Icing up to +300 nm
ahead of surface frontahead of surface front• Icing in clouds and Icing in clouds and
freezing precipitationfreezing precipitation
Cold FrontsCold Fronts • Icing ahead & behind up to Icing ahead & behind up to
+130 nm+130 nm• FZRA/FZDZ aloftFZRA/FZDZ aloft
Occluded FrontsOccluded Fronts • In cloud either side of frontIn cloud either side of front• FZRA/FZDZ possibleFZRA/FZDZ possible
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Checking the WeatherChecking the Weather
Forecast InformationForecast Information• Graphical Area Forecasts (GFA)Graphical Area Forecasts (GFA)• Terminal Area Forecasts (TAF)Terminal Area Forecasts (TAF)• AIRMETSAIRMETS• SIGMETSSIGMETS
ObservationsObservations• METARsMETARs• PIREPSPIREPS
MAKE SURE EVERYTHING
AGREES!
IF IT DOESN’T, UNDERSTAND WHY
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Current/Forecast Icing PotentialCurrent/Forecast Icing Potentialhttp://adds.aviationweather.noaa.gov/http://adds.aviationweather.noaa.gov/
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Checking the WeatherChecking the WeatherWhat you What you NEEDNEED to know to know
Extent of cloud coverageExtent of cloud coverage Cloud topsCloud tops Cloud basesCloud bases Frontal positions (current & forecast)Frontal positions (current & forecast) PrecipitationPrecipitation Freezing levelFreezing level
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Filing the Flight PlanFiling the Flight PlanA Few Things to RememberA Few Things to Remember
ALWAYS HAVE AN OUT FOR EVERY ALWAYS HAVE AN OUT FOR EVERY PHASE OF THE FLIGHT!PHASE OF THE FLIGHT!
Piston aircraft Piston aircraft Reduced thrust marginReduced thrust margin • Usually cruise at 75-85% powerUsually cruise at 75-85% power
Iced wing will not climb as efficientlyIced wing will not climb as efficiently Be mindful of MEABe mindful of MEA Penetrate fronts at a 90 degree anglePenetrate fronts at a 90 degree angle Fly on LEEWARD side of mountain rangesFly on LEEWARD side of mountain ranges
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Monitoring the WeatherMonitoring the WeatherDon’t make it your last priority!Don’t make it your last priority!
A change in weather may warrant the A change in weather may warrant the cancellation of your flightcancellation of your flight
Update Weather and Update Weather and Reassess your outsReassess your outs• PIREPSPIREPS (Icing) (Icing)• METARSMETARS (Clouds,Precipitation,Fronts) (Clouds,Precipitation,Fronts)• ForecastsForecasts (Make sure they are holding) (Make sure they are holding)
Canada (Canada (126.7 MHz126.7 MHz) & US () & US (122.0 MHz122.0 MHz))
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In-Flight StrategiesIn-Flight StrategiesIf Ice is EncounteredIf Ice is Encountered
Start working to get outStart working to get out
Possible Options:Possible Options:• ClimbClimb• DescendDescend• ContinueContinue• DivertDivert• ReturnReturn• Declare an EmergencyDeclare an Emergency
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In-Flight StrategiesIn-Flight StrategiesIf Ice is EncounteredIf Ice is Encountered
RememberRemember::• 90 % of icing encounters are 50 sm or less90 % of icing encounters are 50 sm or less• 9 out of 10 times a change of 3000 ft will 9 out of 10 times a change of 3000 ft will
take you out of icing conditionstake you out of icing conditions Be mindful of MEABe mindful of MEA Be cautious of cloud topsBe cautious of cloud tops
• Use a safe airspeed to maneuverUse a safe airspeed to maneuver• Keep bank angles to a minimumKeep bank angles to a minimum
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In-Flight StrategiesIn-Flight StrategiesDetecting SLDDetecting SLD
RunbackRunback RidgingRidging Ice impingement beyond protected Ice impingement beyond protected
surfacessurfaces Ice on pilots’ side windowsIce on pilots’ side windows Ice on components that usually don’t Ice on components that usually don’t
accrete iceaccrete ice
IF SLD IS SUSPECTED, EXIT IF SLD IS SUSPECTED, EXIT IMMEDIATELYIMMEDIATELY
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NASA Icing Video:NASA Icing Video:Control AnomaliesControl Anomalies