Certified Flight Instructor - Flight Instructor Airplane Practice Exam

What is the expected indication on a magnetic compass when entering a right turn from a southern heading?

1. The compass will initially indicate a left turn.

2. The compass will indicate a right turn, but faster than actual.

3. The compass will remain on the south for a brief period.

4. The compass will rapidly rotate to the new heading.

The correct answer is: The compass will indicate a right turn, but faster than actual.

When entering a right turn from a southern heading, the magnetic compass experiences a phenomenon known as "compass precession." As the aircraft begins to turn, the compass does not immediately reflect the new heading accurately. Instead, it tends to lag behind and initially indicate a turn in the opposite direction (in this case, left) before correcting and showing the actual new heading. The correct indication is that the compass will show the right turn, but it will do so at a rate that is faster than the actual turn. This is due to the magnetic compass's design and the Earth's magnetic field influence as the aircraft's heading changes. This behavior is particularly noticeable when initiating a turn from a southern heading, as the compass momentarily reacts in a way that can lead to a disjointed visual representation of the aircraft's actual turn rate compared to the heading being displayed. It's important for pilots to be aware of this characteristic when interpreting compass indications during flight maneuvers to maintain awareness of their true heading.