Nav 03-04 Flashcards
03/04 What is direction?
The position of one point in space relative to another, without reference to the distance between them.
03/04 What are the cardinal points?
North, South, East, and West.
03/04 What are the quadrantal points?
North East, North West, South East, South West.
03/04 Which system is used in air navigation? (Base 60)
The sexagesimal system. (Angular Distance in Degrees, Minutes, Seconds)
03/04 What is true direction?
Direction measured with reference to the direction of the geographic North Pole.
03/04 What is magnetic direction?
Direction measured with reference to the direction of Magnetic North at the place.
03/04 What are the magnetic poles?
The poles are the position of the greatest field intensity. They are the projection onto the surface of the axis of the Earth’s magnetic field.
03/04 What is the magnetic meridian?
The vertical plane fixed by the direction of the line of force. It is also the direction taken by a perfect compass needle
03/04 What is secular change?
Average value changes in the Earth’s magnetic field over time
03/04 What is a local anomaly?
The anomaly may be natural or it may be artificial. The magnitude depends on the nature of the magnetic material. The effects of these anomalies will decrease rapidly with height above the surface – approx the inverse cube of the distance.
03/04 Define annual variation?
When the average monthly values of the magnetic elements are corrected for the secular change, it is found that there is a small systematic change from month to month. For example the horizontal or ‘H’ component is stronger in summer.
03/04 Define daily change?
There is a small fluctuation of each of the magnetic elements, which repeats itself with some degree of regularity day after day, and is known as the daily change.
03/04 What is a magnetic storm?
Solar flares (sunspots) cause irregularities in the earth’s magnetic field.
03/04 Define soft iron magnetism?
Caused by the magnetism induced into soft material. The soft magnetic material of an aircraft is magnetized by induction of the magnetic field in which they lie. Consists of magnetic fields induced solely by the earth’s magnetic field.
03/04 Define isogonal?
A line on a map joining points of equal variation; not coincident with the magnetic meridian and therefore does not indicate the direction of the earth’s field at a point.
