Private Pilot Glider Practice Test

The magnetic compass can lag behind a change in heading, especially when you roll into a turn. From a north heading, starting a left turn moves the aircraft toward the west, but the compass needle doesn’t instantly follow that change. Instead, due to the way the compass responds to turning motion and its damping in the fluid, the needle temporarily deflects toward the east. So, at the very start of the turn, the compass indicates a turn toward the east even though your actual turn is toward the west. As the turn progresses and the heading stabilizes, the compass will then track the true westward change. This lag can happen specifically when starting from a northerly heading, which is why the initial indication is toward the east rather than toward the direction you’re rolling.