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Weather 2 - Focus on Icing
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Weather 2 - Focus on Icing

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Weather 2 - Focus on Icing Presentation Transcript

  • 1. Welcome Kevin McNulty, Aerospace Education Officer • Email: kevmcnulty@gmail.com • Home phone: 941-729-8928 • Cell phone: 941-737-8575 • Send me email if you would like a copy of this PowerPoint!
  • 2. Welcome Module 3: The Air Environment Part Deaux
  • 3. Overview Module Learning Objectives Chapter 1 - Air Circulation  Describe how the Sun heats the Earth  Describe the Earth’s rotation and revolution and its effect on the seasons  Explain the various theories of circulation  Describe Coriolis Force  Define the jet stream (give three examples…just kidding)
  • 4. Overview Module Learning Objectives Chapter 2 - Weather Elements  Define wind  Describe the Beaufort Scale • Define heat • Explain what temperature is and how it can be expressed • Describe what wind chill is and what it does • Describe how a microburst can affect a plane
  • 5. Overview Module Learning Objectives Chapter 3 - Moisture and Clouds • Describe the condensation process • Describe how saturation occurs • Define dew point • Define what precipitation is and give some examples (not kidding this time) • Define fog • Define turbulence
  • 6. Overview Module Learning Objectives Chapter 4 - Weather Systems and Changes • Define an air mass and their characteristics • Define a front and describe types of fronts • Describe hurricanes, thunderstorms, and tornadoes • Identify the stages of a thunderstorm • Outline safety precautions for thunderstorms and tornadoes
  • 7. Chapter two Temperature and Pressure NOT • Heat = total energy HOT • As heat increases, pressure increases.
  • 8. Chapter three Moisture Water Vapor & Saturation • Water has solid (ice), liquid (water), and gaseous (water vapor) forms • Air always holds some amount of water vapor • Warm air can hold more water vapor than cold air • When air is holding as much water vapor as possible, it is saturated
  • 9. Chapter three Moisture Dew Point, Condensation & Humidity • The temperature at which the air is saturated is called the dew point • When the temperature falls below the dew point, condensation occurs • Clouds and fog are products of condensation • Relative humidity is is the amount of moisture in the air vs. the amount the air can hold (I.e. - 90%)
  • 10. Chapter three Moisture = +
  • 11. Chapter three Moisture Cumulus Formation • Rising air cools • Hits dew pt • Condenses into cloud • Convection = TURBULENCE
  • 12. Chapter three Moisture Precipitation • Condensed water vapor that falls to ground • Examples: rain, snow, ice, hail, ducks, trains • Rain reduces visibility & runway traction • Falling ice/hail can damage aircraft • Snow and freezing rain reduce visibility & traction, but can also lead to icing
  • 13. Focus on Icing Triple Threat • Ice on runway causes loss of directional control, excessive landing roll, and accidents • Ice on aircraft causes excessive weight, loss of lift by altering airfoil camber, loss of thrust by changing propellor camber, visibiity problems on windshield • Ice in engines can cause restricted fuel flow (in carburetor of piston engine) or clogged or malfunctioning sensors in jets
  • 14. icing Air Florida 90 • January 13, 1982, Air Florida 90 failed to achieve takeoff due to ice on airfoil and engines underpowered due to ice/snow-clogged pressure sensors • 4 crew, 70 passengers, 4 on ground killed - 5 survived
  • 15. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • January 1982 was one of the worst periods of exceptionally cold weather in history on the east coast. • For several days, freezing temps had brought traffic to a standstill and interfered with activities around the capital. • On January 13, Washington National Airport had opened at noon under marginal conditions. • That day, AF 90 left Miami International at 11:00 a.m. EST and arrived at National at about 1:45 p.m. EST.
  • 16. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • That afternoon the plane was to return south to Fort Lauderdale-Hollywood International Airport (FLL), with an stop at Tampa International Airport (TPA). • Departure time was delayed about 1 hour 45 minutes due to snow, which temporarily closed the airport. • The aircraft was de-iced by spraying the wings with the monopropylene glycol before leaving the gate.
  • 17. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • AF90 was delayed leaving the gate when the ground services tow motor could not get traction on the ice. • For almost 5 min the crew tried to back away using reverse thrust, which proved futile and evidently resulted in the engines ingesting ice and snow. • Eventually a tug unit properly equipped with snow chains was used to push the aircraft back from the gate. • After finally leaving the gate AF90 waited on taxiway for 49 minutes in line with other aircraft for clearance to use the congested airport's only instrument-rated runway
  • 18. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • The pilot apparently decided not to return to the gate for reapplication of de-icing, fearing the flight's departure would be even further delayed, and chose to continue waiting to take off. • Then, with snow and ice on the airfoil surfaces of the aircraft, the aircraft attempted to take off on the main (and only open) runway in heavy snow at 3:59 p.m. EST.
  • 19. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • Even though it was freezing and snowing, the crew did not activate the anti-ice systems. • Analysis of CVR determined that during the departure checklist, the copilot announced, and the pilot confirmed, that the plane's own anti-icing system was turned off. • Also, the pilots maneuvered closely behind a DC-9 in front of them, thinking the warmth from the DC-9's engines would melt the snow and ice on their wings. (Contrary to flight manual recommendations for an icing situation and actually contributing to icing on the 737.)
  • 20. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • Without the engine anti-icing system the engine pressure ratio (EPR) thrust indicators provided false high readings. • When the pilots thought they throttled up to the correct take-off EPR of 2.04, the actual EPR was only 1.70. • As the plane began its takeoff roll the FO noted several times to the CPT that instrument readings did not seem to reflect reality - the plane did not seem to have developed as much power as it needed for takeoff, despite the instruments indicating otherwise.
  • 21. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • The CPT dismissed the FO’s concerns and let the takeoff proceed. • The captain likely felt pressure to depart quickly because he knew another aircraft was on final approach using the same runway. Indeed, that aircraft landed just as the Air Florida plane took off and had Flight 90 aborted its takeoff the aircraft on final would have been instructed by air traffic controllers to execute a missed approach, delaying its arrival.
  • 22. icing Air Florida Flight 90, January 13, 1982 Sequence of Events Leading up to Crash • Although AF90 did manage to become airborne, it attained a max altitude of just 352 ft before it began losing altitude. The aircraft was airborne for just 30 sec. • At 4:01 it crashed into the 14th Street Bridge across the Potomac River, .75 nm from the end of the runway, hitting 7 vehicles and plunging into the freezing river. • All but the tail section quickly became submerged.
  • 23. icing Air Florida Flight 90, January 13, 1982 Video & CVR
  • 24. icing Air Florida Flight 90, January 13, 1982 NTSB Determination • Probable cause: pilot error • failure to use engine anti-ice • decision to take off with snow/ice on the airfoil surfaces • captain’s failure to reject the takeoff during the early stage when attention was called to anomalous engine instrument readings • maneuvering behind DC9; reverse thrust at gate
  • 25. icing Air Florida Flight 90, January 13, 1982 NTSB Determination • Contributing to the accident • prolonged ground delay between de-icing and the receipt of ATC takeoff clearance during which the aircraft was exposed to continual precipitation • the known inherent pitch up characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice • the limited experience of the flight crew in jet transport winter operations
  • 26. Exercise friendly rivalry Instructions • Individual and team effort needed: make sure you get each others’ phone & email & work together • If you can’t agree, commander makes decision • I will be available at 1730 next two Mondays • Start with wikipedia & www.globalsecurity.org • Summary Reports due by 2100 on AUG 18 •Include map with routes •Aircraft assignments •Individual answer sheets from team members
  • 27. Exercise friendly rivalry Team Member Grade • 70% grade based on individual effort •Answer sheet should be complete and NEAT • 30% grade based on commander’s evaluation of your team effort Team Commander Grade • 50% grade based on individual effort • 50% grade based on mission report, maps, & team communication