The Effects of Weather on Aircraft

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

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

(Note to teacher: Use “Pick a Student” button in CPS) 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Operation Eagle Claw Runs 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

Operation Eagle Claw Runs 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

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

How Wake Turbulence Affects 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

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

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

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

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

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

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

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