General Aviation IcingGeneral Aviation IcingPA Wing Safety Days – Fall 2006PA Wing Safety Days – Fall 2006

Capt William J. Doyle, Jr. Capt William J. Doyle, Jr. Director of Standards and Evaluation, Pennsylvania WingDirector of Standards and Evaluation, Pennsylvania WingCheck Pilot / Instructor-Pilot, FAA Safety CounselorCheck Pilot / Instructor-Pilot, FAA Safety Counselor

CFI A&I, AGI, IGI, ASCCFI A&I, AGI, IGI, ASC

Lesson PlanLesson Plan

• What is icing?What is icing?• How big a problem is icing?How big a problem is icing?• Some icing scenariosSome icing scenarios

– Carburetor Icing (Civilian Cessna 182Q)Carburetor Icing (Civilian Cessna 182Q)– Rime Icing (Civilian Cherokee 180)Rime Icing (Civilian Cherokee 180)– Clear Icing (Civilian Cessna 182R)Clear Icing (Civilian Cessna 182R)– Visible Precipitation (Civilian Cirrus SR20)Visible Precipitation (Civilian Cirrus SR20)

Icing TermsIcing Terms• Icing occurs when liquid moisture comes into contact with Icing occurs when liquid moisture comes into contact with

an object that is at a below-freezing temperature.an object that is at a below-freezing temperature.– Step outside on any bitter cold winter morning. Step outside on any bitter cold winter morning. – Using your moist, above-freezing tongue, lick the below-Using your moist, above-freezing tongue, lick the below-

freezing, metal street post. (Don't try this alone)freezing, metal street post. (Don't try this alone) • Two possible sources of liquid moisture are the above-Two possible sources of liquid moisture are the above-

freezing air below and the above-freezing air above freezing air below and the above-freezing air above – Aircraft icing classified as "clear," "rime," or "mixed." Aircraft icing classified as "clear," "rime," or "mixed." – If source of liquid moisture is the air below, rime ice will form. If source of liquid moisture is the air below, rime ice will form. – If liquid moisture falling as rain from above, clear ice will form. If liquid moisture falling as rain from above, clear ice will form. – If attacking from both directions (e.g. as in a cumulus cloud) the If attacking from both directions (e.g. as in a cumulus cloud) the

icing will be mixed. icing will be mixed. • "Rime" is shorthand for "bad"; "Rime" is shorthand for "bad"; • "clear" is shorthand for "really bad.""clear" is shorthand for "really bad."

Icing Terms Icing Terms (continued)(continued)

• Icing From Above (freezing rain) requires a strong Icing From Above (freezing rain) requires a strong temperature inversion. temperature inversion. – Usually with an advancing warm front Usually with an advancing warm front

• Warm air is elevated as it advances over the underlying cooler airWarm air is elevated as it advances over the underlying cooler air– it expands and cools it expands and cools

• Water vapor condenses into rain in the higher above-melting air, falls into Water vapor condenses into rain in the higher above-melting air, falls into the lower, below-melting air, the lower, below-melting air,

– locates your airplane and turns it into a flying popsicle locates your airplane and turns it into a flying popsicle • Supercooled raindrops are huge in comparison to the supercooled water Supercooled raindrops are huge in comparison to the supercooled water

droplets encountered flying through a clouddroplets encountered flying through a cloud• Supercooled raindrops generate a much greater volume of iceSupercooled raindrops generate a much greater volume of ice

– when your plane runs into them.when your plane runs into them.• The larger drops of liquid readily spread before they freezeThe larger drops of liquid readily spread before they freeze

– that is why the ice is "clear" that is why the ice is "clear"

– For GA pilots, the appropriate precaution for freezing rain is to For GA pilots, the appropriate precaution for freezing rain is to avoid it at all costs.avoid it at all costs.

En Route Icing PrecautionsEn Route Icing Precautions• Be alert for first indication of ice Be alert for first indication of ice

– Movement of air across skin surface heats skin, tends to Movement of air across skin surface heats skin, tends to sweep liquid moisture away before it contacts aircraft sweep liquid moisture away before it contacts aircraft skin skin

– First indications of icing occur in areas of dead air First indications of icing occur in areas of dead air • base of windshield base of windshield • area around OAT probe area around OAT probe • leading edge of wing leading edge of wing

– In those locations, air does not flow smoothly across In those locations, air does not flow smoothly across skin surfaceskin surface

• keeps the skin surface relatively coolkeeps the skin surface relatively cool• prevents airflow from sweeping away liquid moisture prevents airflow from sweeping away liquid moisture

AOPA Air Safety Foundation AOPA Air Safety Foundation Weather Accident StatisticsWeather Accident Statistics

•12% of all weather accidents were due to icing. Of those …12% of all weather accidents were due to icing. Of those …• Induction icing (carburetor ice) leading factor in 52%Induction icing (carburetor ice) leading factor in 52%• Structural icing leading factor in 40%Structural icing leading factor in 40%

Most CAP Most CAP PilotsPilots

Most CAP Most CAP AircraftAircraft

Most Most CommonCommonProblemProblem

AOPA Air Safety Foundation AOPA Air Safety Foundation on Carburetor Icingon Carburetor Icing

• At the first indication of carburetor iceAt the first indication of carburetor ice Apply full carburetor heatApply full carburetor heat LEAVE IT ONLEAVE IT ON

• The engine may run rougher as the ice melts and The engine may run rougher as the ice melts and goes through itgoes through it but it will smooth out againbut it will smooth out again

• When the engine runs smoothlyWhen the engine runs smoothly Turn off the carburetor heat Turn off the carburetor heat

• If you shut off the carburetor heat prematurelyIf you shut off the carburetor heat prematurely the engine will build more icethe engine will build more ice and probably quit because of air starvationand probably quit because of air starvation

Review of FAR 91.103Review of FAR 91.103• FAR 91.103 - Preflight action.FAR 91.103 - Preflight action.

– Each pilot in command shall, before beginning a flight, Each pilot in command shall, before beginning a flight, become familiar with all available information concerning become familiar with all available information concerning that flight. This information must include --that flight. This information must include -- (a)(a) For a flight under IFR or a flight not in the vicinity of an For a flight under IFR or a flight not in the vicinity of an airportairport, , weather weather

reports and forecastsreports and forecasts, fuel requirements, alternatives available if the , fuel requirements, alternatives available if the planned flight cannot be completed, and any known traffic delays of which planned flight cannot be completed, and any known traffic delays of which the pilot in command has been advised by ATC; the pilot in command has been advised by ATC;

(b)(b) For any flight, runway lengths at airports of intended use, and the following For any flight, runway lengths at airports of intended use, and the following takeoff and landing distance information:takeoff and landing distance information:

1)1) For civil aircraft for which an approved Airplane or Rotorcraft Flight For civil aircraft for which an approved Airplane or Rotorcraft Flight Manual containing takeoff and landing distance data is required, the Manual containing takeoff and landing distance data is required, the takeoff and landing distance data contained therein; andtakeoff and landing distance data contained therein; and

2)2) For civil aircraft other than those specified in paragraph (b)(1) of this For civil aircraft other than those specified in paragraph (b)(1) of this section, other reliable information appropriate to the aircraft, relating to section, other reliable information appropriate to the aircraft, relating to aircraft performance under expected values of airport elevation and aircraft performance under expected values of airport elevation and runway slope, aircraft gross weight, and wind and temperature.runway slope, aircraft gross weight, and wind and temperature.

Hypothetical Carburetor Ice ScenarioHypothetical Carburetor Ice Scenario• Engine roughness at night in IMCEngine roughness at night in IMC

– What would you do?What would you do?– Hypothetical PIC applies carburetor heatHypothetical PIC applies carburetor heat

• The roughness worsensThe roughness worsens– What would you do?What would you do?– Hypothetical PIC turns off the carburetor heatHypothetical PIC turns off the carburetor heat

• Now what?Now what?– What would you do?What would you do?– Hypothetical PIC calls ATC and reports situationHypothetical PIC calls ATC and reports situation– ATC offers vectors for an approach and precautionary ATC offers vectors for an approach and precautionary

landing at non-towered field with LOC approachlanding at non-towered field with LOC approach

Hypothetical Rime Ice ScenarioHypothetical Rime Ice Scenario• Icing is in forecast at 5,000 feetIcing is in forecast at 5,000 feet

– What would you do?What would you do?– Hypothetical PIC files IFR flight plan with comments Hypothetical PIC files IFR flight plan with comments

about no altitudes above 3,000 feet due to iceabout no altitudes above 3,000 feet due to ice• Departure clears hypothetical pilot to 5,000 feetDeparture clears hypothetical pilot to 5,000 feet

– What would you do?What would you do?– Hypothetical PIC tries to negotiate clearance but Hypothetical PIC tries to negotiate clearance but

ultimately climbs to 5,000 feetultimately climbs to 5,000 feet• Rime ice immediately begins to form. Now what?Rime ice immediately begins to form. Now what?

– What would you do?What would you do?– Hypothetical PIC gets immediate descent to 3,000 feetHypothetical PIC gets immediate descent to 3,000 feet– Rime ice sticks until out of clouds at 1,700 feetRime ice sticks until out of clouds at 1,700 feet

Hypothetical Clear Ice ScenarioHypothetical Clear Ice Scenario• Windshield and leading edges ice over in day VFRWindshield and leading edges ice over in day VFR

– What would you do?What would you do?– Hypothetical PIC continues practice ILS approachHypothetical PIC continues practice ILS approach

• The windshield ice won’t dislodgeThe windshield ice won’t dislodge– What would you do?What would you do?– Hypothetical PIC continues practice ILS approachHypothetical PIC continues practice ILS approach

• Now what?Now what?– What would you do?What would you do?– Hypothetical PIC flies ILS below DHHypothetical PIC flies ILS below DH– Hypothetical PIC uses side windows for landingHypothetical PIC uses side windows for landing– After sitting for an hour on ramp, ice still in placeAfter sitting for an hour on ramp, ice still in place

ASI Failure Scenario in Visible PrecipASI Failure Scenario in Visible Precip• ILS approach in IMC (clouds and rain)ILS approach in IMC (clouds and rain)

– What would you do?What would you do?– Hypothetical PIC flies ILS approach without pitot heatHypothetical PIC flies ILS approach without pitot heat

• The airspeed indicator (ASI) goes to zeroThe airspeed indicator (ASI) goes to zero– What would you do?What would you do?– Hypothetical PIC pitches down about 15Hypothetical PIC pitches down about 15º º 20º 20º

• Now what?Now what?– What would you do?What would you do?– Hypothetical PIC cross-checked other instruments Hypothetical PIC cross-checked other instruments – Hypothetical PIC flew approach to successful outcomeHypothetical PIC flew approach to successful outcome

Preparation to Cope with ASI FailurePreparation to Cope with ASI Failure• Pre-Flight Knowledge Areas

– Understand flight instrument cross-check and correlation.– Understand Flight Instrument Perspectives of an ASI

Failure.– Know power settings for various flight profiles.

• In-Flight Situational Awareness– Periodically correlate ASI airspeed with GPS groundspeed

for a given flight regime or direction of flight.– Know wind direction and velocity for each flight leg

• Get frequent updates from Flight Watch, ATIS, ASOS, and ATC

– Activate Pitot Heat at first sign of visible precipitation

Instrument Cross-Check for Failed ASI

ASI Failure EnrouteASI Failure Enroute• Cross-check Flight Instruments to verify level flight

attitude– Attitude Indicator (AI): miniature airplane on horizon– Altimeter (ALT): altitude is constant at assigned altitude– Vertical Speed Indicator (VSI): needle on zero

• When nearing destination airport– Reduce power setting to a descent profile.– Cross-check using groundspeed indicated on GPS– Extend flaps to approach setting

ASI Failure on Vectors to Approach• Reduce power to setting to obtain an airspeed of 90

to 120 Kts, depending on aircraft• Cross-check using the groundspeed indicated on the

GPS• When slowed and stabilized, extend flaps to

approach setting• Cross-check Flight Instruments to verify level flight

attitude– AI: miniature airplane on the horizon– ALT: altitude is constant at assigned altitude– VSI: needle on zero

ASI Failure on Precision Approach• When established, reduce power to obtain 90-100 Kts• Cross-check using the groundspeed indicated on GPS• Check VSI for 500 - 600 FPM rate of descent• Intercept Glideslope (GS) and follow GS prompts on HSI• If above Glideslope

– Reduce power slightly (1" - 2" MP or 100 RPM)– Pitch down slightly to acquire GS– When GS acquired, adjust power and pitch to maintain GS

• If below Glideslope– Increase power slightly (1" - 2" MP or 100 RPM)– Pitch up slightly to acquire GS– When GS acquired, adjust power and pitch to maintain GS

• At Decision Height (DH) and airport complex in sight– Reduce power to landing power setting– Extend flaps to full– Pitch for 500 FPM rate of descent on VSI– Pre-landing checklist (GUMP)– Gradually reduce power to idle when runway is "made"

ASI Failure on Non-Precision Approach• When established, reduce power to obtain 90-100 Kts• At Final Approach Fix (FAF)

• Start time • Check VSI for 700 - 750 FPM rate of descent • Level off at Minimum Descent Altitude (MDA)

• If above MDA • Reduce power slightly (1" - 2" MP or 100 RPM)• Pitch down slightly to acquire MDA • When MDA acquired, adjust power and pitch to maintain MDA

• If below MDA • Increase power slightly (1" - 2" MP or 100 RPM)• Pitch up slightly to acquire MDA • When MDA acquired, adjust power and pitch to maintain MDA

• At Missed Approach Point (MAP) and airport complex in sight– Reduce power to landing power setting– Extend flaps to full– Pitch for 500 FPM rate of descent on VSI– Pre-landing checklist (GUMP)– Gradually reduce power to idle when runway is "made"

SummarySummary• Get a thorough weather briefingGet a thorough weather briefing

– Thoroughly review Winds and Temperatures aloftThoroughly review Winds and Temperatures aloft– Understand the lapse rate and how it relates to your Understand the lapse rate and how it relates to your

planned altitude and route of flightplanned altitude and route of flight

• PIC needs to … PIC needs to … – Apply pitot heat at first sign of visible precipitationApply pitot heat at first sign of visible precipitation– Apply carb heat at first sign of engine roughnessApply carb heat at first sign of engine roughness

• Keep carb heat on until engine runs smoothKeep carb heat on until engine runs smooth

– Determine power settings for various flight regimesDetermine power settings for various flight regimes• MP settings and RPM settingsMP settings and RPM settings

Credits and CitationsCredits and Citations

• Doyle, William J., Jr., Emergencies: Airspeed Indicator Failure, Cirrus SR20 Transition Training, January 2003.

• Puddy, R. Scott, Icing — Taking Adequate Precautions, AVweb, July 2002.– http://www.avweb.com/news/airman/181876-1.html

• Puddy, R. Scott, Flying Into Known Icing — Is It Legal?, AVweb, July 2002.– http://www.avweb.com/news/airman/181877-1.html

• FAA General Aviation Pilot’s Guide to Preflight Weather Planning, Weather Self-Briefings, and Weather Decision Making.

• AOPA-ASF Aircraft Icing, Pamphlet SA11 .• AOPA-ASF Aircraft Deicing and Anti-Icing Equipment,

Pamphlet SA22.

About the PresenterAbout the Presenter

• AviatorAviator– Commercial, Instrument, ASEL & AMEL – 2,600 hours total time; 500 hours TAA; 500 hours KFC 150; 600 hours Garmin 430

• InstructorInstructor– CFI A&I, AGI, IGI, ASC– 1,200 hours as CFI– Cessna FITS Course and CFAI Course

• Civil Air PatrolCivil Air Patrol– Instructor-Pilot and Check-Pilot– PA Wing Director of Standards & Evaluation

• Technologist & TeacherTechnologist & Teacher– Director of Technical Services, Hatboro-Horsham School District– Computer Science Instructor, La Salle University

• AuthorAuthor– Two books on electronic spreadsheets, with a Russian translation– Self-study manuscript on computer concepts for nurses– Articles on gear up landings and fuel management published by FAA

Aim High!Aim High!But Not On Final!But Not On Final!