Definition
The lines of force of a magnetic or electric field. Flux is a measure of the total field passing through a given area, and its strength and direction determine how that field interacts with conductors, magnetic materials, or sensing elements.
Plain English
The invisible field — magnetic or electric — flowing through a space. The more flux passing through something, the stronger the field is acting on it.
Context Anchor
Seen in discussions of magnetos, generators, alternators, compass systems, and flux valves, which are compass sensors that detect Earth’s magnetic field.
Derivation
From Latin fluxus, meaning 'a flowing.' The word was adopted because early scientists pictured magnetic and electric fields as something that flowed through space, like a current of water through a channel.
Why Pilots Care
Reliable flux sensing gives accurate heading information, essential for navigation when visual references are unavailable.
Analogy
Think of flux like an invisible pattern around a magnet. You cannot see it directly, but equipment designed for it can react to it, much like a compass needle reacts to Earth’s magnetism.
Grounding Statement
Picture a magnet held near a coil of wire — the invisible magnetic field passing through the coil is the flux. Move the magnet, and the changing flux produces a voltage in the wire.
Intuition Check
Flux does not just mean “change” here. In this aviation context, it means magnetic force or magnetic field lines that equipment can use or detect.
Example Sentence 1
When the magneto's rotating magnet spins past the coil, the changing flux induces a voltage that fires the spark plug.
Example Sentence 2
During the IFR flight the pilot cross-checked the heading indicator against the flux-derived reference.