Navigational Elements

Discussion What other steps do you think the American pilots could have taken to navigate to friendly territory? Read page 262 Chapter 4, Lesson 1 © Anthony DiChello/ShutterStock, Inc.

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 Objectives  Identify key navigation instruments outside the cockpit  Identify key navigation instruments inside the cockpit  Describe how pilots determine flight position  Describe how pilots determine navigational direction  Identify problems associated with chart projections (maps)  Identify the four main goals of chart projections (maps)  Describe how different geometric types of chart projections (maps) are developed along with benefits and drawbacks Chapter 4, Lesson 1

Vocabulary  Air Navigation  Heading  Track  Vector Chapter 4, Lesson 1

Navigation   Air navigation is the act of flying from one place to another   Two ways to navigate: by sight or with instruments   Early Airmail pilots flew day and night to finish their routes.   During the day they could follow railroads, paved roads, and familiar buildings and landscapes.   At night they used bonfires and other bright lights (beacons)   In the early the 1920s, the government developed the four- course radio range a radio navigation beacon system   Used four towers to send out four signals in Morse code at each station. Chapter 4, Lesson 1

Navigational Instruments   In the 1920s and 1930s instruments began to show up in the cockpit to help aid pilots   Two way radios   Altimeter—an aircraft instrument that displays altitude   Directional gyroscope—known as an attitude indicator   Vertical speed indicator   Airspeed indicator   Heading indicator (Compass) Chapter 4, Lesson 1

Navigational Instruments, cont.   As instruments inside the cockpit improved, instruments outside the cockpit also improved   In the 1940’s, radar was invented helping air traffic control communicate location to aircraft   By the 1950s VHF-VOR began replacing the four-course radio range   By 1970s, satellites soared onto the scene; tracked aircraft and broadcast their locations to ground stations Chapter 4, Lesson 1

Correlation of Latitude and Longitude to Flight Position   Pilots can find the position of any point on the earths surface by referring to both its latitude and longitude   Circles parallel to the equator are called lines of latitude   Equator is the starting point for measuring north-south   Great Circles that pass through both the North and South Poles are meridians and are called lines of longitude   The Prime Meridian is 0 degrees longitude Chapter 4, Lesson 1

How to Determine Navigational Direction   Pilot draws a line on a chart from departure point to the destination to indicate the course   The pilot then measures the angle this line makes with the meridians it will cross   A plane’s heading is the direction in which an aircraft nose is pointing during flight.   An 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

The Problems Associated With Chart Projections (Maps)   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

Chart Projection Characteristics   Charts (maps) portray four main characteristics: area, shape, distance, and direction. There are four main goals :   Equivalent projection charts - illustrate true area   Conformal projection charts – show true shapes   Equidistant projection charts —represent true distance   Azimuthal or Zenithal projection charts – represent true direction   Cartographers base their charts on three geometric projections, which are the cylinder, the cone, and the plane Chapter 4, Lesson 1

Cylinders   If you slice the cylinder open along a meridian and spread out the chart   Parallels and meridians meet at right angles.   Direction is true and represented by straight lines.   However, it only maintains shapes in small areas and distorts shapes, distances, and areas as the it nears the poles   Cylinder projection—best for navigating along the equator Chapter 4, Lesson 1

Cones   Conical projections seats a cone over the sphere of the Earth and projects the surface conformally on to the cone   To read a conic chart projection, you roll it out after cutting it open along a meridian   Because it is conformal, shapes and areas also fair well near the parallels   However, shapes and areas begin to warp the farther they get from the two parallels.   Conformal conic projection— best for trips following an east- west route Chapter 4, Lesson 1 Courtesy of NASA

Planes   The stereographic plane projection is a way of picturing the sphere as the plane   It is the only projection that maps all circles of a sphere to circles.   It sends meridians to rays emanating from the origin and parallels to circles centered at the origin.   Stereographic projections are used to chart polar regions   Another common plane projection is the gnomonic chart   Gnomonic chart projection — shortest route between two points Chapter 4, Lesson 1 Reproduced from US Geological Survey

Discussion Personal Application How do you decide where you are? How do you determine the direction you are going? What kind of maps to you use? Chapter 4, Lesson 1 © Anthony DiChello/ShutterStock, Inc.

Lesson Objectives  Identify key navigation instruments outside the cockpit  Identify key navigation instruments inside the cockpit  Describe how pilot determine flight position  Describe how pilots determine navigational direction  Identify problems associated with chart projections (maps)  Identify the four main goals of chart projections (maps)  Describe how different geometric types of chart projections (maps) are developed along with benefits and drawbacks 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

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

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

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