Definition
Small adjustable magnets built into the magnetic compass housing that are used to cancel out deviation errors caused by the aircraft's own magnetic fields. They are set during a compass swing procedure to minimize the difference between the compass reading and the actual magnetic heading.
Plain English
Tiny magnets inside the compass that a technician can turn to correct the compass when the aircraft's own metal and electrical parts pull the needle off course.
Context Anchor
Seen when the magnetic compass is checked or adjusted on the ground, especially after installation, maintenance, or changes to nearby electrical equipment.
Derivation
From Latin compensare, meaning 'to weigh against' or 'offset.' These magnets offset, or counterbalance, the unwanted magnetic pull from the aircraft itself.
Why Pilots Care
Proper adjustment keeps heading information reliable, reducing the risk of navigation errors or spatial disorientation when flying by instruments.
Intuition Check
Compensating magnets do not make the compass perfect. They only reduce the compass error caused by the airplane’s own magnetic effects.
Example Sentence 1
During the annual inspection, the technician adjusted the compensating magnets to reduce deviation on north and east headings.
Example Sentence 2
After installing new radios, the pilot had the compensating magnets readjusted to restore accurate compass performance.