inertia switch

inertia switch

[i′nər·shə ‚swich] (electricity) A switch that is actuated by an abrupt change in the velocity of the item on which it is mounted.

inertia switch

An electrical switch that is actuated by the sudden acceleration of an aircraft. Inertia switches are used in emergency locator transmitters, which get activated when the aircraft decelerates rapidly during crash landings.