What can a compass indicate when the aircraft is turning to the South with deceleration?

When an aircraft turns to the South while decelerating, the compass provides essential information about the aircraft's orientation and direction. During this turn, the compass will accurately indicate that the aircraft is turning to the South.

In aviation, the compass is a crucial instrument for navigation, and its readings are influenced by the aircraft's heading and movement. As the aircraft banks in a turn toward the South, the magnetic compass aligns itself with the Earth's magnetic field, reflecting the change in direction.

The indication that the aircraft is turning to the South is vital for maintaining proper flight path and ensuring accurate navigation. It confirms the pilot's intention to change direction and provides feedback on the effectiveness of the turn.

This reasoning highlights why the compass reading is related to the turn itself, and understanding this helps pilots use the compass effectively during maneuvers. Other options do not directly relate to the primary function of the compass during the turn, making the focus on the indication of the turn to the South the most relevant and accurate choice.