During a level 360º turn, the magnetic compass will read most accurately on which headings?

The magnetic compass reads most accurately during a level 360º turn when the aircraft is headed toward either 90º (east) or 270º (west). This accuracy during these headings can be attributed to the way a magnetic compass functions.

When an aircraft is on headings of 90º or 270º, the magnetic dip – the tendency of the compass to align itself with the Earth's magnetic field – is reduced since the compass is equidistant from the magnetic poles. On these headings, the compass is least affected by acceleration and turning errors, which are more significant when the aircraft is on north/south headings.

At 0º (north) and 180º (south), the compass is more susceptible to errors due to magnetic variation and dip, as it aligns more directly with the magnetic field lines that run vertically. Similarly, at 45º or 225º, the compass will exhibit increased turning and acceleration errors as the aircraft progresses through the northern quadrant where these errors are amplified.

By understanding the magnetic compass behavior, pilots can anticipate possible inaccuracies and manage their navigation and flight planning more effectively during various phases of flight, especially while executing turns.