When swinging a magnetic compass, what are compensators adjusted for?

The adjustment of compensators when swinging a magnetic compass is done specifically to correct for magnetic influence deviation. This deviation occurs due to local magnetic fields generated by the aircraft itself and other surrounding influences. The compensators are small magnets strategically placed within the compass housing that allow for calibration, enabling the compass to provide accurate heading information despite these magnetic interferences.

During the compass swinging process, the aircraft is typically rotated on a level plane to allow the compass to align correctly with the Earth's magnetic field. The compensators are adjusted to account for any discrepancies observed in the compass reading due to the aircraft's structure and electronic equipment, ensuring that the compass responds accurately to magnetic north.

In contrast, the other options relate to different concepts not directly linked to the adjustments made during the swinging process. Instrument fatigue pertains to wear and tear on the instruments over time, static pressure variations relate to altimeter readings, and altitude discrepancies are generally associated with altitude measurement rather than magnetic heading references.