Navy IFS Stage I Practice Exam

When an aircraft is accelerated or decelerated in the Northern Hemisphere, the magnetic compass tends to indicate accurately when the aircraft is on a north or south heading. This behavior is due to the alignment of the magnetic compass with the Earth's magnetic field, which is strongest near the poles and where the magnetic meridians align closely with true north and south.

On the north or south headings, the compass is least affected by acceleration or deceleration effects, as the magnetic variation and those forces are in direct alignment. During acceleration, the compass may show a turn towards the north, and during deceleration, it might indicate a turn towards the south. However, when the aircraft is on a north or south heading, these transient variations are minimized, allowing for an accurate reading.

Other choices might suggest inaccurate compass behavior under specific conditions related to turning or climbing, which does not hold true for the simple north/south orientation where steadiness in reading occurs due to reduced error from the magnetic influences and aircraft movement.