Final answer:
The speedbrake handle on an aircraft's control pedestal is used to deploy spoilers to various extents to slow the aircraft down. The degree to which spoilers can be extended varies by aircraft model but usually ranges from partial to full extension.
Step-by-step explanation:
The speedbrake handle on the control pedestal is a component found in an aircraft's cockpit which pilots use to extend the spoilers. Spoilers are control surfaces on the wing of an aircraft that can be raised to disrupt airflow and reduce lift, thus slowing the aircraft down. The extent to which the spoilers can be deployed by the speedbrake handle can vary depending on the aircraft model but typically ranges from partially to fully extended.
When the handle is pulled upwards or backwards, spoilers are raised on the wing surfaces to different degrees to help decelerate the aircraft during descent, approach, or after landing. It's important for pilots to follow procedures for the use of the speedbrake, as excessive use can lead to decreased control or structural damage to the aircraft.