Which system is primarily responsible for the movement of the ailerons and elevators?

Which system is primarily responsible for the movement of the ailerons and elevators?

• A. SECs
• B. FACs
• C. ELACs
• D. PCUs

Answer: (C)

The Elevator and Aileron Computers (ELACs) are responsible for the movement of the ailerons and elevators. They take the pilot’s sidestick input (and autopilot as applicable), apply the current flight-control law, and generate the surface-deflection commands for roll and pitch. Those commands are then sent to the hydraulic actuators (Power Control Units) to physically move the surfaces. The other computers play supportive roles rather than direct surface movement. SECs handle spoiler coordination and some elevator functions in certain modes, but they’re not the primary source of the direct aileron/elevator commands. FACs provide flight augmentation and law logic, shaping how commands are interpreted and applied, but they don’t directly drive the surfaces in normal operation. PCUs are the hydraulic actuators that execute the commanded movements, not the control logic itself. So the ELACs are the main system that directly governs the ailerons and elevators.

The Elevator and Aileron Computers (ELACs) are responsible for the movement of the ailerons and elevators. They take the pilot’s sidestick input (and autopilot as applicable), apply the current flight-control law, and generate the surface-deflection commands for roll and pitch. Those commands are then sent to the hydraulic actuators (Power Control Units) to physically move the surfaces.

The other computers play supportive roles rather than direct surface movement. SECs handle spoiler coordination and some elevator functions in certain modes, but they’re not the primary source of the direct aileron/elevator commands. FACs provide flight augmentation and law logic, shaping how commands are interpreted and applied, but they don’t directly drive the surfaces in normal operation. PCUs are the hydraulic actuators that execute the commanded movements, not the control logic itself.

So the ELACs are the main system that directly governs the ailerons and elevators.