ERAU Instrument Checkride Practice Test

The correct answer is based on the two acronyms used to help pilots remember the specific errors that occur in magnetic compass behavior: “ANDS” and “NOSS.”

“ANDS” stands for Acceleration North, Deceleration South, indicating how the magnetic compass reacts to changes in speed. When an aircraft accelerates while flying on a north heading, the compass will momentarily show a turn towards the east. Conversely, when decelerating on a north heading, the compass might indicate a turn towards the west.

“NOSS” refers to the errors introduced when the aircraft is turning. "N" stands for North, which indicates that during a turn, the compass lags while turning to the east and leads while turning to the west. These behaviors highlight the magnetic compass's tendency to respond differently based on the aircraft's orientation and movement, emphasizing the need for pilots to be aware of these discrepancies when navigating.

Both acronyms collectively cover important aspects of magnetic compass errors and are essential for understanding compass behavior during flight. Recognizing the significance of these two sets of terms ensures that pilots can effectively interpret compass readings, particularly in critical flying conditions.