Nav 03 / 04 - Direction on the Earth and Magnetism Flashcards
Review Questions
Define Meridian
Semi-great circle joining the poles of the Earth
Review Questions
Define Parallel of Latitude
Small circle on the earth whose plane is parallel to the plane of the equator
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Define Rhumb Line
A regularly curved line on the surface of the earth cutting all meridians at the same angle
Review Questions
What is a NM?
Length of arc on the surface of the Earth subtending 1’ at the center of the curvature of the plane
Review Questions
What is a Great Circle?
A circle of the surface of the Earth, whose radius and center are that of the sphere itself.
Define Direction
The position of one point in space relative to another, without reference to the distance between them
What are the Cardinal points?
N S E W
What are the Quadrantal Points?
NE, NW, SE, SW
Describe the Sexagesimal system
It is the system used in Air Navigation.
Angular distance in Degrees, Minutes and Seconds
60 sec to one minute and 60 minutes to one degree
Expresses both time and direction
Define the following Cardinal directions
East
West
North
South
East - The direction which the earth is spinning
West - The direction opposite to East
North - The direction of the North Pole
South - The direction opposite to North
Define True Direction
A direction measured with reference to the direction of the geographic North Pole
Define Magnetic Direction
A direction measured with reference to the direction of the Magnetic North at the place
What is an Agonic line?
A line where all variation is zero
How is the magnetic field around Earth produced?
The motions of molten iron in the Earth’s core
The True North and South represent the geographic points for what?
Earth’s rotation
The Magnetic Poles are the projection onto the Earth’s surface of what?
Earth’s magnetic field
True or false
Both the North and South magnetic poles are stationary
False, they both move
Will a straight line drawn from one pole to the other pass through the geometric center if the Earth? Why or not?
(Seek more clarification on the wording)
No, it will not because the Earth’s magnetic field is not symmetrical.
Define Magnetic Meridian
Slide 18 mentions “horizontal component”, the notes under the slide mentions “vertical plane”.
The direction of the horizontal component of earth’s magnetic field as a point.
A compass needle will align itself with the MM, pointing to the magnetic North Pole.
Define Secular Change
Average value changes in Earth’s magnetic field over time, reflecting changes in the Earth’s core. It is unpredictable.
Define Local Anomaly
May be natural or man-made.
Intensity of anomaly depends on nature of the magnetic material and the height above the material.
Define Annual Variation
Average monthly values of the magnetic elements are corrected for secular change.
It is found that there is a small systematic change from month to month
Define Daily Change
There is a small fluctuation of each of the magnetic elements, which repeats itself day after day with some regularity daily. This is known as daily change.
Define a Magnetic Storm
A solar flares which occurs when a cloud of magnetic fields are released from the sun. The Earth’s magnetic elements are disturbed by the particle emission of the solar flare.
These sun storm disturbances of the magnetic elements are called magnetic storms.
Define Soft Iron Megnetism
Caused by the magnetism induced into soft material.
Consists of magnetic fields induced solely by the earth’s magnetic field.
Varies with changes in heading and magnetic latitude
Define Isogonal
A line on the map joining parts of equal variation. Not coincident with the magnetic meridian and therefore does not indicate the direction of the earth’s field at a point.
Define Agonic Line
A line on a map joining points of zero variation
Define Compass Direction
Direction measured with respect to compass north.
Define Variation
The horizontal angle between true north and magnetic north
True of false
Variation is considered East or West depending on whether magnetic direction is East or West of true direction
True
Define Hard Iron Magnetism
Best described as the AC’s own magnetic field caused by the magnetism present within an AC’s structure/ onboard systems.
What are some characteristics of Hard Iron Magnetism?
Remains constant with changes to heading and magnetic latitude
Considered permanent
For our sake, the three components are combined into one deviation
What are the different components of Hard Iron Magnetism?
Component:
P - parallel to longitudinal axis of the AC
Q - Parallel to the lateral axis of the AC
R - Parallel to the vertical axis of the AC
Define Deviation
The angular difference between compass north and magnetic north
What causes deviation?
Magnetic material and electrical disturbances within the AC cause the deviating effects
Describe Compass North
It is the direction taken by the compass needle
Review Questions
Direction may be defined as the position of one point in space relative to another without reference to?
Distance between them
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Direction measured with reference to the aircraft’s fore and aft axis defines
Relative direction
Review Questions
Magnetic direction is defined as the direction measured with reference to the direction of?
Magnetic north at the place
Review Questions
The horizontal angle between true north and magnetic north at any place defines?
Variation
Review Questions
Define Deviation
The angular distance between compass heading and magnetic heading
