How is primary control of the flight control surfaces accomplished?

Primary control of the flight control surfaces in modern aircraft, including the Embraer Regional Jets, is accomplished using fly-by-wire technology. This system replaces conventional mechanical linkages and control rods with electronic interfaces. By using sensors to detect pilot inputs, the fly-by-wire system processes these commands and sends signals to the flight control surfaces.

Fly-by-wire technology enhances maneuverability and precision in controlling the aircraft. It allows for various performance optimizations, such as load alleviation and stability augmentation. Additionally, this technology limits the aircraft's response to avoid excessive maneuvers that could lead to overstress or loss of control, providing a safer flying experience.

The other methods listed, while they are part of flight control systems in different aircraft designs, do not encapsulate the primary means used in modern jets. Mechanical systems alone lack the precision and flexibility provided by electronics, hydraulic systems are typically components of the control system rather than the primary control method, and manual controls, while still present for pilot input, are not the sole basis of flight control in fly-by-wire systems.