Final answer:
To command an Open Climb or an Open Descent, vertical speed values are inputted into the Flight Control Unit (FCU) to instruct the aircraft to climb or descend at a desired rate.
Step-by-step explanation:
In aviation, the terms 'Open Climb' and 'Open Descent' are often used to describe specific vertical commands given to the autopilot system known as the Flight Control Unit (FCU). To command an Open Climb, the pilot or air traffic controller would input a vertical speed value into the FCU, indicating the rate at which the aircraft should climb. Similarly, to command an Open Descent, a vertical speed value is inputted to instruct the aircraft to descend at a desired rate.