10 / 20
Which of the following statements is correct as regards the operational use of a Direct Reading Compass (DRC)? The DRC…
  • A
    requires no power from the aircraft systems to indicate direction.
  • B
    is free from interference from other aircraft systems and components.
  • C
    is only certified for use under VFR and during published hours of daylight.
  • D
    is more reliable than a directional gyro during turns and periods of acceleration or deceleration.
A freely suspended magnet will align itself with the Earth's magnetic field, requiring no power from the aircraft systems to indicate direction. The total field (T) is resolved into a horizontal component (H) and a vertical component (Z). The horizontal component is the part that is detected by the compass needle in order to determine Magnetic North. The compass’ needle will align itself with the Earth's horizontal component (H) of the Earth's magnetic field.
  • The compass is ineffective near the poles. As you approach the poles, the angle between magnetic flux and the horizon becomes vertical – compass ‘dip’ becomes a factor => decrease in the horizontal magnetic field, increase in the vertical magnetic field.
  • The value of the horizontal component is maximum at the Magnetic Equator, a freely suspended compass needle in the Earth's magnetic field will be horizontal to the Earth - in line with the horizontal component.

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.

Keyboard Shortcut Use Keyboard Shortcuts