Definition
A set of small adjustable magnets mounted near the magnetic compass that is used to cancel out deviation errors caused by the aircraft's own electrical systems and ferrous metal components. The compensator assembly is adjusted during a compass swing so that the compass reads as accurately as possible on the cardinal headings.
Plain English
A small built-in set of correction magnets next to the compass. They are tweaked on the ground to push the compass needle back toward the correct heading, cancelling out the magnetic pull from the aircraft itself.
Context Anchor
Seen in magnetic compass discussions, especially when learning how aircraft-caused compass error is checked and reduced.
Derivation
Compensator comes from the Latin compensare, meaning to balance or counterweigh. The assembly does exactly that: it balances out unwanted magnetic pull from the aircraft so the compass can show true magnetic heading.
Why Pilots Care
Accurate compass headings are required for navigation and instrument flight; uncorrected deviation can produce heading errors that accumulate into significant track deviations.
Grounding Statement
The airplane can act like a small magnet, and the compensator assembly helps counter that pull so the compass reads more accurately.
Intuition Check
The compensator assembly does not make the compass perfect. It only reduces the error caused by the aircraft’s own magnetic effects; the pilot still uses the posted compass correction information when needed.
Example Sentence 1
After installing the new radio, the mechanic adjusted the compensator assembly and updated the compass correction card.
Example Sentence 2
Before an IFR flight the pilot checked the deviation card posted near the compass and confirmed the compensator assembly settings had not changed since the last annual.