The flaps are powered by which hydraulic system(s)?

The flaps on the A320 are primarily powered by two hydraulic systems: the green and yellow systems. The green hydraulic system provides the majority of the power required for flap operation, ensuring reliable and robust performance during key phases of flight, such as takeoff and landing.

The yellow system serves as a backup and provides additional hydraulic pressure, ensuring that even if the primary system fails, the flaps can still operate safely. This dual-system architecture enhances safety and reliability, which is essential for critical control surfaces like flaps. The ability to utilize two systems means that the aircraft can maintain functionality even in the event of a hydraulic failure.

In contrast, the blue hydraulic system is primarily used for other functions, such as powering the flight controls and landing gear, and does not contribute directly to flap operation. This design reflects Airbus's focus on redundancy and safety in their aircraft systems.