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Using the UNOS rule, what happens to the magnetic compass when rolling out onto a northerly heading?
Choices
It leads the actual heading, so you roll out late
Leading occurs on southerly headings, not northerly.
✓ It lags the actual heading, so you must roll out early (undershoot)correct
UNOS: undershoot north — the compass lags, so lead the rollout by stopping the turn early.
It reads exactly correct throughout the turn
Turning error is greatest near north and south, not zero.
It spins continuously and cannot be used
The compass still functions; it simply exhibits turning error.
Why
UNOS means Undershoot North, Overshoot South. Rolling out onto north, the compass lags the actual heading, so the pilot stops the turn early (undershoots) to arrive on heading.
FAA source: PHAK Ch. 8browse the reference library →
Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.