General Navigation

Question 1

What are the lines which run from pole to pole called?

Answer 1

Meridians of longitude

Question 2

What are the lines that run east to west called?

Answer 2

Parallels of latitude

Question 3

Latitude is measured as an angle from the _______.

Answer 3

Equator

Question 4

Longitude is measured as an angle from the ______.

Answer 4

Prime meridian

Question 5

To calculate the change in latitude of two points in the same hemisphere ____ the angles.

Answer 5

subtract

Question 6

To calculate the change in latitude of two points in different hemispheres ____ the angles.

Answer 6

add

Question 7

To calculate the change in longitude of two points in the same hemisphere ____ the angles.

Answer 7

subtract

Question 8

To calculate the change in longitude of two points different hemispheres ____ the angles.

Answer 8

add

Question 9

What do you do if chlong is greater than 180°?

Answer 9

Subtract it from 360° to find the shortest way round.

Question 10

How do you find the position of the opposite point on the earth?

Answer 10

Latitude: same ° but opposite hemisphere

Longitude: 180 - ° and in the opposite hemisphere

Question 11

What is the ratio of elipticity of the earth?

Answer 11

1/298

Question 12

Geocentric latitudes are measured from the ______.

Answer 12

Centre of the earth

They do not intersect the surface at 90°

Question 13

Geodetic lattitudes are measured _______.

Answer 13

At 90° to the earth’s surface.

They are used for charts.

Question 14

What is the difference from equator to pole in km?

Answer 14

10,000km

Question 15

What is the earth’s circumference in km?

Answer 15

40,000km

Question 16

1’ = ___NM

Answer 16

1

Question 17

1° = ___NM

Answer 17

60

Question 18

What is departure used to calculate?

Answer 18

The east/west distance along a parallel of latitude (not the shortest distance)

(needed as the distance between meridians of longitude decreases as latitude increases)

Question 19

What is the formula for departure?

Answer 19

Departure (NM) = Chlong (minutes) x cos lat

Question 20

If asked to find the shortest distance between points with different longitudes AND diferent latitudes…

Answer 20

It will be over the pole from a meridian to its antimeridian

Question 21

What is convergency?

Answer 21

How much the great circle track changes because of converging meridians.

Question 22

What are directions referenced to the geographic north pole called?

Answer 22

True north

Question 23

Give 2 examples of great circles

Describe great circles in terms of track direction and distance between two points.

Answer 23

Equator, all meridians of longitude

Constinuously changing track direction (unless both points on equator or same longitude)

Shortest distance between points

Question 24

What is the formula for convergency?

Answer 24

Convergency = chlong x sin(mean lat)

Question 25

Rhumb lines have ________ direction and lie on the __________ side of the equivalent great circle.

Answer 25

constant equatorial

Question 26

Where do the great circle track and rhumb line track have the same direction?

Answer 26

halfway

Question 27

What is the conversion angle and how is it calculated?

Answer 27

The angle between the great circle and the rhumb line. Conversion angle = ½ convergency

Question 28

Which lines on the earth are rhumb lines?

Answer 28

All parallels of latitude.

Question 29

Whch angle does magnetic variation represent?

Answer 29

The angle between the true meridian and the magnetic meridian.

Question 30

Which lines join points of equal variation?

Answer 30

Isogonals

Question 31

'Variation east, magnetic \_\_\_\_\_ variation west, magnetic \_\_\_\_'

Answer 31

least best

Question 32

Concerning variation, consider east as ______ and west as \_\_\_\_\_\_.

Answer 32

positive negative

Question 33

What is the difference between the direction of magnetic north and compass north called?

Answer 33

Deviation

Question 34

'Deviation ____ compass least, deviation ____ compass best.'

Answer 34

East West

Question 35

What causes deviation to vary?

Answer 35

Magnetic latitude (strength of Earth's magnetic field) Aircraft heading (orientation of aircraft to magnetic field) Changes of aircraft electrical equipment (production of interfereing magnetic fields)

Question 36

Cadbury's Dairy Milk Very Tasty is a pneumonic for what?

Answer 36

Compass Deviation Magnetic Variation True

Question 37

The directive force is the component of the Earth's magnetic field that \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 37

Aligns the compass needle.

Question 38

When should a compass swing be carried out?

Answer 38

Transfering bases with significant latitude change After major changes of aircraft equipment After lightning strike After its been parked facing one direction for a long time When a new compass is fitted When compass or recorded deviation is suspect When specified in the maintenance schedule

Question 39

What is the maximum permissable deviation for a magnetic compass (current EASA regulations)?

Answer 39

+/- 10°

Question 40

If variation is west then true north is ____ of magnetic north.

Answer 40

east

Question 41

What 3 properties do conformal/orthomorphic charts have?

Answer 41

Shows shapes, angles and distances correctly Same scale used for latitude and longitude Meridians and parallels are perpendicular

Question 42

What is the formula for chart scale?

Answer 42

chart scale = chart distance / earth distance

Question 43

Where is a projected chart most accurate?

Answer 43

The parallel of origin (where it touches the model)

Question 44

How is a simple conic projection derived? Convergency is ________ and calculated using the formula : \_\_\_\_\_\_\_

Answer 44

Placing a cone on a wire globe constant convergency = chlong x sin parallel of origin

Question 45

How does the accuracy of convergency effect great circles on a map?

Answer 45

Accurate convergency shows great circles as straight lines Increasing inaccuracy makes great circles more curved

Question 46

Where is the parallel of origin on a Lamberts Conformal Projection?

Answer 46

Parallel to the tangent of the sphere

Question 47

On Lamberts conformal projections how does scale vary with the standard parallels and parallel of origin?

Answer 47

Contracts between standard parallels, expands outside them Scale at minimum value at parallel of origin Can be assumed constant though

Question 48

What 2 conditions must be met by a lamberts conformal projection in order to assume the great circle lines to be straight and the scale to be constant?

Answer 48

max latitude spread of 24° max 2/3rds of chart between the standard parallels

Question 49

On lamberts conformal projection rhumb lines are concave to \_\_\_\_\_\_\_.

Answer 49

the nearest pole

Question 50

On a polar stereographic chart _____ can be assumed constant. Rhumb lines are concave to \_\_\_\_\_\_. Great circles are assumed straight but are actually \_\_\_\_\_\_\_. Convergency = \_\_\_\_\_\_\_\_

Answer 50

scale the nearer pole concave to the pole convergency = chlong (sin lat at pole, 90°, is 1)

Question 51

On a mercator projection chart scale can be assumed constant within ____ NM of the equator. Which lines are straight and which are curved? (great circles, rhumb lines, meridians, parallels)

Answer 51

500NM rumb lines, meridians, prallels and the equator are straight great circles are concave to the equator

Question 52

On a mercator projection what is convergency?

Answer 52

zero

Question 53

How is scale calculated on a mercator projection?

Answer 53

Scale at any latitude = scale at equator x sec(lat)

Question 54

Great circles always lie on the ________ side of rhumb lines.

Answer 54

poleward