Definition
A system that automatically corrects a directional gyro by continuously aligning it with magnetic north using signals from a remote magnetic sensor (the flux detector or flux valve), typically mounted in a wingtip or tail away from magnetic interference. The slaving system combines the steady reference of a gyro with the magnetic accuracy of a compass, producing a heading indication that is both stable and accurate without requiring the pilot to manually reset it.
Plain English
A setup that keeps the heading indicator pointed correctly to magnetic north on its own, by quietly comparing the gyro's reading to a magnetic sensor in the wing and nudging it back into line whenever it drifts.
Context Anchor
Seen in discussions of ADF and RMI navigation displays, where a bearing pointer is read against a heading card.
Derivation
From the older engineering term 'slave,' meaning a device that follows or is driven by another. Here, the directional gyro is 'slaved' to the magnetic sensor — it follows the magnetic reference rather than running independently.
Why Pilots Care
Prevents gradual heading drift in the gyro, maintaining accurate navigation references during ADF use and instrument flight.
Intuition Check
“Slaving” does not mean the autopilot is flying the airplane. Here it means one instrument display is automatically following a heading source.
Example Sentence 1
Before takeoff, the pilot checked the slaving system by watching the slaving meter centre, confirming the heading indicator was tracking magnetic north correctly.
Example Sentence 2
A failure in the slaving system caused the heading indicator to drift during the flight.