FAA Ground School Practice Test

In the northern hemisphere, what will a magnetic compass indicate when a right turn is made from a north heading?

1. It will indicate a turn toward east

2. It will indicate a turn toward west

3. It will remain neutral

4. It will spin randomly

The correct answer is: It will indicate a turn toward west

When a magnetic compass is used in the northern hemisphere and a right turn is made from a north heading, the compass experiences a phenomenon known as "turning error" or "compass precession." As the aircraft begins the right turn, the compass tends to lag behind and indicates a turn toward east initially. However, during a right turn from north, the magnetic compass will actually lag in its indication. This means that instead of showing the correct heading to the east right away, the compass will indicate a turn toward west temporarily due to the inertia of the magnetic needle. This occurs because the compass is designed to align itself with magnetic north, but it is also affected by the forces acting on it when the aircraft changes its orientation. As a result, the compass deviates from the true path, showing a incorrect heading before it eventually stabilizes and reflects the true direction of the aircraft. The other answer options do not accurately describe the behavior of the compass in this situation. The compass does not simply remain neutral or spin randomly; it attempts to point toward magnetic north but does so with a lag, resulting in an initial misreading.