Auto-spoilers

Auto-spoilers automatically command full ground and flight spoiler deployment upon touchdown, reducing stopping distances, brake wear and pilot workload. Generally they are activated by landing gear strut compression (weight-on-wheels), with some systems performing partial deployment when the main landing gear compress, followed by full deployment once the nose gear strut is compressed. This behaviour helps to plant the aircraft firmly onto the runway surface, increasing wheel brake effectiveness and reducing the changes of bouncing when approach speeds are higher (eg, in wind-shear conditions)

See also auto-brakes