Which characteristics are true for aircraft hydraulic systems?

Aircraft hydraulic systems are known for their lightweight design, minimal maintenance requirements, and high operating efficiency, which contribute significantly to their performance in aviation applications. These systems rely on fluid mechanics to transmit power, making them highly effective for different functions such as controlling flight surfaces, landing gear, and brakes.

The lightweight characteristic is vital in aviation as it contributes to overall aircraft performance, including fuel efficiency and maneuverability. Minimal maintenance is also a crucial aspect because it reduces downtime and operational costs for airlines and ensures greater reliability in critical flying operations. Additionally, the high efficiency of hydraulic systems, often around 80 percent or more, allows for effective power transfer with less energy loss.

Having simple inspection processes further supports the operational efficiency as it facilitates quick checks and ensures that any issues can be identified and addressed with minimal effort, enhancing the safety and reliability of the aircraft. Therefore, the combination of these attributes makes option D the most accurate description of aircraft hydraulic systems.