FAA Ground School Practice Test

What happens to the magnetic compass indication when rolling into a standing rate turn to the right from a south heading?

1. The compass will indicate a turn to the left

2. The compass will indicate a turn to the right, but at a faster rate

3. The compass will indicate no turn

4. The compass will indicate an abrupt change

The correct answer is: The compass will indicate a turn to the right, but at a faster rate

When rolling into a right turn from a south heading, the magnetic compass demonstrates a phenomenon known as magnetic compass precession. In this case, as the aircraft begins the right turn, the compass initially indicates a turn to the left before settling into the actual turn. This happens because the compass is influenced not only by the magnetic heading but also by the motion of the aircraft. During the transition into the turn, as the aircraft begins to bank, the compass tends to lag and show a slower rate of turn compared to the actual rate of the aircraft's heading change. As the aircraft continues to roll into the right turn, the compass corrects its indication and eventually reflects a right turn, but the overall effect during the initiation of the roll can create the impression of a faster rate of turn than might be intuitively expected. This characteristic of the magnetic compass leads to the situation described, where the compass might indicate a right turn but not precisely matched to the actual rate, creating a more complex understanding of instrument readings during maneuvers.