Final answer:
The FCC (Flight Control Computer) that is currently active or in command is the only FCC that can control the trim actuators in an aircraft. They make necessary adjustments to maintain level flight and reduce pilot workload.
Step-by-step explanation:
When considering what FCC (Flight Control Computer) can control trim actuators, it's important to understand that the trim actuators are integral components in an aircraft's flight control system. Trim actuators make small adjustments to the control surfaces of an aircraft, like the elevator, ailerons, or rudder, to alleviate control forces and to maintain the aircraft in level flight without continual pilot input.
In modern aircraft, the autopilot system, which is managed by the Flight Control Computer (FCC), has the authority to control these trim actuators. However, a specific implementation may vary among different aircraft, and usually, each FCC can command the trim actuators when it is in control. There is often more than one FCC on board for redundancy, but only the FCC that is currently active or in command will control the trim actuators at any given time. In the event of a system failure, control may be transferred to another FCC, or manual overrides can allow the pilot to control the trim manually.