The Effects of Weather on Aircraft

1. The Effects of Weather on Aircraft

2. Warm-Up Questions CPS Questions 1-2 Chapter 2, Lesson 5

3. Lesson Overview • How ice impacts flight • How a microburst can induce wind shear on an aircraft • How sandstorms can be hazardous to air flight • How wake turbulence affects air flight Chapter 2, Lesson 5

4. Quick Write Do you think good flying instincts are something you’re born with or a skill you can learn? (Note to teacher: Use “Pick a Student” button in CPS) Chapter 2, Lesson 5 Courtesy of NASA

5. How Ice Impacts Flight • 13 January 1982 Air Florida Flight 90 took off from Washington National Airport • Snow was falling fast • Plane was barely airborne before crashing into 14th Street Bridge • The 737’s nose pitched up abruptly right after liftoff Chapter 2, Lesson 5 Courtesy of AP Photo

6. Causes of the Crash • Flight crew didn’t turn on engine anti-ice system • Crew took off even though snow and ice covered the airfoils • Captain should have heeded irregular readings from engine instruments • Pilot and copilot’s limited winter flight experience Chapter 2, Lesson 5 Reproduced from National Transportation Safety Board

7. Ice Hazards • Can cause stalls, make it difficult to see out the windshield • Icing takes place when a plane flies through visible water—cloud or fog • Wind chill can cool airplane’s surface enough that icing can occur Chapter 2, Lesson 5 Courtesy US Air Force/Staff Sgt Joseph McKee

8. Forms of Ice • Clear—glossy, see-through • Rime—brittle and frostlike • Mixed—mixture of clear and rime Chapter 2, Lesson 5 Reproduced from NASA/virtual skies

9. Lift and Weight • If ice builds up on an aircraft, plane’s weight increases—lift decreases • When aircraft is about to stall, you can often feel it vibrate • Snow and ice change an airfoil’s shape and reduces lift Chapter 2, Lesson 5 Reproduced from National Transportation Safety Board

10. Drag • Snow and ice buildup also generates drag • Induced drag always accompanies lift; drag and lift always proportional • Parasite drag can be a problem for plane contaminated with ice and snow Chapter 2, Lesson 5

11. Activity 1: Icing Research Tunnel • Watch the video “NASA at 50: Icing Research Tunnel Designated as Historic Landmark” • Answer the analysis questions Chapter 2, Lesson 5

12. Learning Check Questions CPS Questions 3-4 Chapter 2, Lesson 5

13. Microburst • Is a violent downdraft • Takes place in space of less than one mile horizontally and within 1,000 feet vertically • Lasts about 15 minutes, and can create wind speeds greater than 100 knots Chapter 2, Lesson 5 Courtesy of NASA

14. Effects of a Microburst • Plane experiences a quick series of events • Performance-increasing headwinds • Performance-decreasing downdrafts • Wind rapidly shearing to a tailwind • Impact with the ground or aircraft pushed dangerously close to the ground Chapter 2, Lesson 5 Reproduced from US Department of Transportation/Federal Aviation Administration

15. Detecting Microbursts • Difficult because they crop up in relatively small areas • Often associated with convective precipitation • Airports have installed a low-level wind shear alert system • NASA, FAA and others developed sensor that reads speed and direction of invisible particles of water vapor and dust in the wind Chapter 2, Lesson 5 Courtesy of NASA

16. Activity 2: Effects of a Microburst • Examine the illustration • Answer the questions and explain what is occurring with the aircraft and the weather Chapter 2, Lesson 5

17. Activity 3: Flight 191 and Flight Safety • Review the Delta Air Lines Flight 191, Dallas, Texas section in the textbook • Investigate research and gather information using the sources identified Chapter 2, Lesson 5

18. Learning Check Questions CPS Questions 5-6 Chapter 2, Lesson 5

19. Sandstorms • Strong, dry winds generally take place over arid—hot and dry—lands • Reduce visibility, clog aircraft engines and instruments, and make it difficult to breathe • Can damage aircraft and other machinery Chapter 2, Lesson 5 Courtesy of USN/USMC/Cpl Alicia M. Garcia

20. Operation Eagle ClawRuns Into Sandstorms • Military troops were attempting to rescue 53 Americans who had been taken hostage • It was to take place over two nights • Weather played large part in ending the mission prematurely • MC-130s and EC-130s ran into two sandstorms • Helicopters had to spread out to avoid running into one another Chapter 2, Lesson 5 Courtesy of USAF/Hurlburt Fielditt

21. Operation Eagle ClawRuns Into Sandstorms, cont. • One helicopter crew aborted due to damaged rotor blade; another’s navigation and flight instruments failed; yet another had mechanical issues • Col Beckwith recommended aborting the mission • Eight Airmen and Marines died Chapter 2, Lesson 5 Courtesy of USAF/Hurlburt Field

22. Activity 4: Sandstorms in Aviation • Review the Operation Eagle Claw Runs Into Sandstorms section in the textbook • Outline the events of the mission specific to the sandstorm in the flow chart Chapter 2, Lesson 5

23. How Wake TurbulenceAffects Air Flight • Aircraft generate wake turbulence while in flight • Disturbance caused by a pair of vortices trailing from an aircraft’s wingtips • Dangerous to other aircraft that get too close • Can damage aircraft parts and equipment Chapter 2, Lesson 5 Courtesy of NASA/Sarah DeWitt

24. Intensity • Depends on weight, speed, and wing shape of vortex-producing aircraft • Greatest when the generating aircraft is heavy, slow, and clean • Strong wingtip vortices created during takeoff, climb, and landing Chapter 2, Lesson 5 Reproduced from US Department of Transportation/Federal Aviation Administration

25. Vortex Behavior • Trailing vortices behave in predictable ways that can help pilots avoid wake turbulence • Move outward, upward, and around the wingtips • Vortices generally maintain a distance of a little less than a wingspan apart Chapter 2, Lesson 5 Reproduced from US Department of Transportation/Federal Aviation Administration

26. Avoiding Wake Turbulence • Avoid flying through another aircraft’s flight path • The pilot should climb above the other aircraft’s climb path until clear of its wake • When landing behind a departing aircraft, land before the departing aircraft’s rotating point Chapter 2, Lesson 5 Reproduced from US Department of Transportation/Federal Aviation Administration

27. Learning Check Questions CPS Questions 7-8 Chapter 2, Lesson 5

28. Summary • How ice impacts flight • How a microburst can induce wind shear on an aircraft • How sandstorms can be hazardous to air flight • How wake turbulence affects air flight Chapter 2, Lesson 5

29. Review Questions CPS Questions 9-10 Chapter 2, Lesson 5

30. Next…. • Done – the effects of weather on aircraft • Next – human physiology and air flight Chapter 2, Lesson 5 Courtesy of USAF/MSgt Kevin J. Gruenwald