Northerly Turning Error
What is northerly turning error?
Northerly turning error is a magnetic compass error that occurs when an aircraft turns to or from a northerly or southerly heading. As you start a turn from north, the compass briefly lags and shows a turn in the opposite direction, while turning from south it leads and shows a faster turn than actual. This happens because the vertical component of the Earth's magnetic field pulls on the compass card during banked turns. On the test, remember the memory aid "UNOS" — Undershoot North, Overshoot South — when rolling out of a turn.
Also known as: compass turning error, turning error
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