Definition
The internal moving part of a magnetic compass, consisting of a buoyant card carrying the compass magnets, suspended on a pivot inside a sealed bowl filled with a clear damping fluid. The float supports the magnets so they can swing freely and align with the Earth's magnetic field, while the fluid steadies its motion and reduces oscillation.
Plain English
The part inside a magnetic compass that floats in liquid and turns to point north. The compass card you read is attached to it.
Context Anchor
Seen in magnetic compass discussions, especially when explaining why the compass can show turning errors in certain directions.
Derivation
Called a 'float' because it literally floats in fluid -- the buoyancy reduces the weight pressing on the pivot, letting the magnets turn smoothly and respond to small magnetic forces.
Why Pilots Care
Ensures the compass card can move freely and display accurate headings during turns, directly affecting the severity of acceleration and turning errors.
Intuition Check
Do not read “float assembly” as aircraft floats or landing gear for water operations. Here it means the floating internal compass part that carries the direction display.
Example Sentence 1
Because the float assembly is suspended in fluid, it takes a moment to settle after a turn, which is why pilots wait for the compass to stabilise before reading it.
Example Sentence 2
When the float assembly functions correctly, the pilot sees smoother heading indications during a standard-rate turn.