1

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

6565

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))

6767

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

6969

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