Navigational Elements

Warm-Up Questions CPS Questions 1-2 Chapter 4, Lesson 1

Chapter Overview   Lesson 1: Navigational Elements   Lesson 2: Navigational Aids   Lesson 3: Dead Reckoning and Wind   Lesson 4: Flight Instrumentation   Lesson 5: Navigation Technology Chapter 4, Lesson 1

Lesson Overview  The history of navigation and navigation instruments  The relationship of Earth's size and shape to navigation  The correlation of latitude and longitude to flight position  How to determine navigational direction Chapter 4, Lesson 1

Lesson Overview, cont.  Chart projection characteristics  How chart projections are used in navigation  The problems associated with projections Chapter 4, Lesson 1

Quick Write What other steps do you think the American pilots could have taken to navigate to friendly territory? (Note to teacher: Use “Pick a Student” button in CPS) Chapter 4, Lesson 1 © Anthony DiChello/ShutterStock, Inc.

Navigation  Air navigation is the act of flying from one place to another  Keep tabs on your position as flight progresses  Two ways to navigate: by sight or with instruments  Bonfires and other bright lights Chapter 4, Lesson 1

Navigational Instruments   1920s: government developed a radio navigation beacon system   Mid- to late 1920s: developed two-way radios, other instruments began to show up   Altimeter—an aircraft instrument that displays altitude   Directional gyroscope—known as an attitude indicator Chapter 4, Lesson 1

Navigational Instruments, cont.  Airspeed indicator  Turn-and-bank coordinator  1941: ultrahigh-frequency (UHF) radio range  1944: very high frequency (VHF) Chapter 4, Lesson 1 Courtesy of the Minnesota Department of Transportation

Navigational Instruments, cont.  1940’s: Radar also popped up; helps air traffic control maintain safe distances between aircraft  1967: Satellites soared onto the scene; tracked aircraft and broadcast their locations to ground stations Chapter 4, Lesson 1 Courtesy of NASA

Relationship of Earth’s Size and Shape to Navigation  Earth’s shape is referred to as the great circle  Equator is a great circle because its center is also Earth’s center  Circle that passes through both the North and South Poles is a great circle, its center is Earth’s center  Great circle navigation—shortest distance across a sphere’s surface between two points Chapter 4, Lesson 1

Learning Check Questions CPS Questions 3-4 Chapter 4, Lesson 1

Correlation of Latitude and Longitude to Flight Position  Pilots calculate locations in degrees, minutes, and seconds of arc  Equator is the starting point for measuring north- south locations; circles parallel = lines of latitude  Great Circles that pass through both the North and South Poles; meridian = lines of longitude   Prime meridian is 0 degrees longitude   Pilots can find the position of any point by referring to both its latitude and longitude Chapter 4, Lesson 1

Activity 1: Finding a Flight Position  Locate cities based on given coordinates  Find the coordinates of given cities  Calculate distances Chapter 4, Lesson 1

How to Determine Navigational Direction  Pilot draws a line on a chart from departure point to the destination—the course  Measures the angle this line makes with the meridians it will cross  Aircraft’s track is the actual path taken over the ground in flight  When plotting a course, they determine their vector, an aircraft’s direction and speed Chapter 4, Lesson 1 Reproduced from US Department of Transportation/Federal Aviation Administration

Activity 2: Determining Direction  Make a compass rose  Find items or locations  Determine directions Chapter 4, Lesson 1

Learning Check Questions CPS Questions 5-6

Chart Projection Characteristics  Charts portray four main characteristics: area, shape, distance, and direction  Illustrate true area—equal-area or equivalent projections  Show true shape—conformal chart projections  Represent true distance—equidistant projections  True direction—azimuthal or zenithal Chapter 4, Lesson 1

Geometry  Cartographers base their charts on three geometric projections, which are the cylinder, the cone, and the plane Chapter 4, Lesson 1 Adapted from National Atlas of the United States

Cylinders  Cylinder forms an image of Earth in one of two ways  Tangent—wraps around Earth along a single line such as the equator or a meridian  Secant—encircles Earth along two lines  Mercator projection is the most common example of cylinder chart Chapter 4, Lesson 1 Reproduced from US Geological Survey

Cones  Cone projection’s peak can line up with Earth’s polar axis  To read a conic chart projection, you roll it out after cutting it open along a meridian  Lambert conformal conic is one type of conic chart Chapter 4, Lesson 1 Courtesy of NASA

Planes  A plane is tangent to a point rather than a line  Stereographic projection— used to chart polar regions  The point the image is projecting from is always on the opposite side of the globe from the point of tangency  Another common plane projection is the gnomonic chart Chapter 4, Lesson 1 Reproduced from US Geological Survey

Chapter 4, Lesson 1 Learning Check Questions CPS Questions 7-8

How Chart Projections Are Used in Navigation  Gnomonic chart projection— shortest route between two points  Stereographic plane projection— navigating around the poles  Lambert conformal conic projection— best for trips following an east-west route  Mercator projection—best for navigating along the equator Chapter 4, Lesson 1 Courtesy of NASA

Activity 3: Chart Projections  Create a presentation on a chart projection and its use in air navigation  Conduct further research using the sources identified Chapter 4, Lesson 1

The Problems Associated With Projections  Difficult to convert a sphere to a flat surface without distorting some part of the original image  Distortions tend to be far greater when chart tries to cover large regions  Direction is at least partly true for most navigation chart projections Chapter 4, Lesson 1

Activity 4: Aeronautical Charts  Explore NASA’s Virtual Skies section on Aviation Navigation to learn more about aeronautical charts  Answer the questions Chapter 4, Lesson 1

Learning Check Questions CPS Questions 9-10

Summary Chapter 4, Lesson 1  The history of navigation and navigation instruments  The relationship of Earth's size and shape to navigation  The correlation of latitude and longitude to flight position  How to determine navigational direction

Summary, cont. Chapter 4, Lesson 1  Chart projection characteristics  How chart projections are used in navigation  The problems associated with projections

Chapter 4, Lesson 1 Review Questions CPS Questions 11-12

Next….  Done – navigational elements  Next – navigational aids Chapter 4, Lesson 1 Reproduced from US Department of Transportation/Federal Aviation Administration