Definition
An electrical switch that opens or closes its contacts when it senses a specified rate of acceleration or deceleration. It is typically used to automatically activate or deactivate a circuit during sudden changes in motion, such as a crash or hard landing.
Plain English
A switch that turns a circuit on or off when it detects a sudden change in motion, like a sharp jolt or rapid slowdown.
Context Anchor
Seen in aircraft electrical and safety systems, especially equipment that must activate automatically after a hard impact.
Derivation
From the Latin 'accelerare' meaning 'to hasten' or 'to speed up.' In this context, 'acceleration' includes any change in speed -- speeding up, slowing down, or sudden impact -- so the switch reacts to any sharp change in motion, not just speeding up.
Why Pilots Care
Provides automatic system response during high-G maneuvers or crash conditions without requiring pilot action.
Intuition Check
Do not read “acceleration” here as only speeding up. In this term, it can also mean a sudden stop, impact, or change in motion strong enough to operate the switch.
Example Sentence 1
When the aircraft struck the ground, the acceleration switch closed and activated the emergency locator transmitter.
Example Sentence 2
In the aerobatic aircraft, the acceleration switch monitored G-forces to illuminate the overstress warning light.