Plain English Meaning

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.

Full 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.

Context Anchor

Seen when the magnetic compass is checked or adjusted on the ground, especially after installation, maintenance, or changes to nearby electrical equipment.