1. Aviation Hazard Awareness Training Jody James, Senior Forecaster Icing

2. Aircraft Icing…not often encountered… Dangerous for all Aviation

3. The Worst Conditions for Icing From USA Today Website

4. We Will Cover: Types of Icing Types of Icing Where is Ice Encountered? Where is Ice Encountered? De-Icing Equipment De-Icing Equipment What to Do If Ice Is Encountered? What to Do If Ice Is Encountered? Icing Forecasts Icing Forecasts

5. Types of Icing Clear - A glossy, clear or translucent ice formed by the relatively slow freezing of large supercooled water droplets. Rime - Rough, milky, opaque ice formed by instantaneous freezing of small supercooled water droplets. Mixed - Mixture of rime and clear ice.

6. What Temperature Ranges…for 0 to –20 degrees Celsius Warmer – No Ice Colder – water droplets convert to ice crystals

7. What Temperature Ranges…for Can…However get Ice in Temperatures –25 or colder Especially in T-stms… Big Droplets and Strong Lifting… Big Droplets and Strong Lifting…

8. Where are Icing Conditions Usually Worse?? Near the tops of Clouds…larger drops – still very small, on the order of 10 to 50 microns. (A human hair is around 100 microns.) Freezing Precipitation - The worst icing occurs when aircraft encounter supercooled liquid water in the drizzle drop size (30- 300 microns diameter). The ATR crash was in freezing drizzle – not well understood.

9. Thunderstorm – Severe Icing 20 miles!!

10. ATR Icing Accident A twin turbo-prop ATR-72 nose-dived into a soybean field near Roselawn, Indiana, on Oct. 31, 1994, killing everyone on board: four crewmembers and 64 passengers. The NTSB attributed the aircraft's loss of control to a sudden and unexpected movement of an aileron -- a flight control on the wing -- that occurred after a ridge of ice formed behind the plane's deice boots -- mechanisms that shed in-flight ice buildup from the wings. This occurred behind the ice boots and resulted in aileron reversal. On October 31, 1994, an ATR-72 commuter aircraft crashed near Roselawn, Indiana, killing 64 passengers and 4 crew members. Aircraft icing was the cause.

11. Safety Rules in Ice Hand Fly the Aircraft to Check Aerodynamics In GA Aircraft – Use De-ice equipment to flee from the ice, not fly in the ice… Read POH Most Ice Accidents occur not in the ice, but during landing after acquiring ice. Stall Speed will increase….be careful with slow and low maneuvering. Keep Speed Up on Approach if heavily iced!!

12. Safety Rules in Ice Treat Ice Like Smoke in the Cockpit, – Do something about it! Options: Climb – May be warmer temperatures above Descend – to warmer temperatures, watch out for MSA/terrain. Divert – alternate airport Return – 180 course reversal…this may be best option.

13. Aircraft De-Icing and Anti-icing Pitot Icing - Responsible for a lot of accidents. Airspeed indicator will act like altimeter Partial Protection – prop de-ice, windscreen de-ice – use when in clouds below 0 degrees C. Ice Boots – some equipment not approved for flight in icing. Has Aircraft been tested in ice – ex. Homebuilts. Wanna be a test pilot?? OF INTEREST>>> The weight of 1 inch of ice is usually negligible…50 to 100 lbs…most of the loss of efficiency is due to the disfiguring of the airfoil. Ice on propeller also small effect compared to airframe ice.

14. Other Icing Information can be obtained from Aviation Weather Center Page at: www.aviationweather.gov

15. Official Icing Forecasts are obtained from AIRMETS - ZULU DFWZ WA 121445 AIRMET ZULU UPDT 2 FOR ICE AND FRZLVL VALID UNTIL 122100. NO SGFNT ICE EXPCD OUTSIDE OF CNVTV ACT.. FRZLVL...060-080 N OF INK-SAT-MLU-MSL-HMV LN RSG TO 120-140 OVR LWR RIO GRANDE VLY OF S TX..... Ft. Worth AIRMET Zulu Icing and Freezing Levels

16. Official Icing Forecasts are obtained from AIRMETS - ZULU MIAZ WA 121445 AIRMET ZULU UPDT 2 FOR ICE AND FRZLVL VALID UNTIL 122100. AIRMET ICE...NC SC GA FL AND CSTL WTRS FROM 170E ORF TO 140SSE ILM TO CRG TO 50SW ABY TO GQO TO HMV TO 170E ORF OCNL MOD RIME/MXD ICGICIP BTN 140 AND FL270. CONDS CONTG BYD 21Z THRU 03Z.. FRZLVL...100-120 NW OF MGM-ORF LN SLPG TO 140-160 S OF 180SSW CEW-140SSE ILM LN. Miami AIRMET Zulu Icing and Freezing Levels

17. Other Forecasts Useful When Icing is a Concern TAF TAF KLBB 121130Z 061212 36014GKT 3SM –FZDZ BR OVC020 Winds and Temps Aloft 3000 6000 9000 12000 18000…… 39000 LBB 3409+03 3410-03 3314-10 3475-12 3387-24

18. Other Forecasts Useful When Icing is a Concern PIREP JFK UA /OV JFK180005/TM 1649/FL250/TP LR25/IC MOD RIME= Be careful using PIREPS… 1.Not all ice is reported… 2.Ice Can Develop or Dissappear Quickly 3.What Type of Aircraft Reported the Ice? A Jet at 250 knots may report no ice…while in a Cessna 172…you report a light frost…WHY??? Several degrees warming of skin temp due to friction!

19. Other Forecasts Useful When Icing is a Concern Icing Airmets and Sigmets Aviation Weather Center - aviationweather.noaa.gov

20. Icing Forecasts Icing Potential Forecasts CIP and FIP Aviation Weather Center - aviationweather.noaa.gov

21. Icing Forecasts Freezing Level Graphics Aviation Weather Center - aviationweather.noaa.gov

22. Icing Forecasts Pilot Reports Aviation Weather Center - aviationweather.noaa.gov

23. Aviation Hazard Awareness Training – Thunderstorms Jody James, Senior Forecaster

24. Aircraft icing is one of the major aviation hazards for which forecasters must advise pilots. Significant icing is very dangerous because accumulation of ice affects aircraft performance. In just a matter of minutes, an aircraft can ice up to a point where maintaining control becomes very difficult. The worst icing occurs when aircraft encounter supercooled liquid water in the drizzle drop size (30-300 microns diameter). Obvious weather conditions are temperatures below zero degrees Celsius and environments with high relative humidity. However, in order for these drizzle drops to form, the atmosphere must be undergoing upward vertical motion at slightly faster speeds than the large-scale lifting that forms large cloud masses (about 1 cm/sec). Too much upward vertical motion and water drops larger than drizzle-size quickly develop. The optimum vertical motion is on the order of 10 cm/sec. One likely cause of vertical motion of this magnitude is the slowing down of convective bubbles as they encounter decelerating forces. This condition occurs frequently at cloud tops, and is a good explanation of why significant icing is often observed there. The patterns of the conditions for significant icing (temperature, relative humidity, and slight convective potential) are numerous and quite complex. They do not lend themselves to typical input/output prediction schemes. An artificial intelligence tool that does very well at pattern recognition is a neural network. A neural network is a simple version of a mammalian brain. A neural network is "taught" to recognize input data patterns and to identify with what conditions these input patterns are associated. A neural network is pure rote learning, like a gradeschooler learning multiplication tables. Neural networks work well in complex pattern recognition because they are very non-linear. That means that they can handle situations which cannot be expressed in a straight-forward logical thought-stream. The maps of icing intensity are composites of the output of two neural networks taught to predict icing intensity from input data of temperature, relative humidity, and convective potential from the Rapid Update Cycle model. Actual output to the Aviation Weather Center forecasters is in layers approximately 1000 ft thick. The output values range from zero to six with zero representing no icing and six severe icing. A two is light icing and a four is moderate icing. The contours begin at the two level. While fours are very common, a five (moderate to severe icing) is rare. Because of the contouring routine, you will never see a six.Rapid Update Cycle This is experimental output. The Experimental Forecast Facility at the Aviation Weather Center is evaluating the output to see if there are any flaws. Anyone using this product as a flight-briefing aid should always consult the latest Aviation Weather Center icing advisories.icing advisories Donald W. McCann Donald W. McCann AWC Research Meteorologist