What is the defining feature of "fly by wire" technology?

The defining feature of "fly by wire" technology is its reliance on electronic controls for flight management. This system replaces traditional mechanical linkages, allowing pilots to control the aircraft through electronic signals sent from the flight control inputs to the control surfaces. The use of sensors, computers, and actuators enhances the precision and responsiveness of the aircraft's handling characteristics.

Fly by wire systems allow for advanced features such as flight envelope protection, automatic stability augmentation, and easier integration of advanced autopilot capabilities. This technology improves safety and performance, providing pilots with more reliable and nuanced control, while also helping to reduce the weight of the aircraft by eliminating certain mechanical components.

In contrast, options that suggest mechanical linkages or manual systems do not represent the rationale behind fly by wire technology, which fundamentally shifts control from hydraulic and mechanical systems to electronic means. Additionally, the notion of operating solely on autopilot oversimplifies the capability of fly by wire systems, which still require pilot input, although they can facilitate autopilot functions effectively.