The hydraulic system pressure in the A380 is increased to 5000 psi, allowing for a weight reduction of over 1000 kg due to smaller equipment and components. A key design feature is the placement of main hydraulic components in the pylons, optimizing Engine Driven Pumps (EDPs) function and eliminating high points between the reservoir and the EDP.
The EDPs on the A380 can be declutched, protecting them in case of hydraulic leakage or uncontrolled fluid overheating – a necessity due to the integration of fuel/hydraulic heat exchangers.
The Airbus A380’s hydraulic power system has two electrical backup systems, Electrical System 1 and 2. These systems replace the traditional blue hydraulic system and are primarily used for flight controls, enhancing redundancy. Notable for their weight-saving benefits and redundancy improvement, these systems include Electrical Back-up Hydraulic Actuators (EBHA) and Electro-Hydrostatic Actuators (EHA).
The A380’s Ram Air Turbine (RAT) generates electrical rather than hydraulic power, driving an electrical emergency generator for emergency power. The hydraulic systems are cooled by two fuel/hydraulic heat exchangers per circuit, one in each pylon, and use metal bellow accumulators for hydraulic pressure surge damping and high flow demand.
The A380’s hydraulic system is split into two independent circuits, green and yellow, powering flight actuators, landing gears, braking, and cargo doors. Hydraulic power is produced by Engine Driven Pumps (EDP) in flight and Electric Motor Pumps (EMP) on the ground. The aircraft’s flight controls have electrical backup through EHAs and EBHAs, with the slats and Trimmable Horizontal Stabilizer Actuators (THSA) powered by electrical motors. Landing gear braking and steering systems also have electrical backups through a Local Electrical Hydraulic Generation System (LEHGS).
Each hydraulic circuit in the A380 has its pressurized reservoir, with reservoirs located in the outboard pylons. The hydraulic generation system includes components like pumps, reservoirs, heat exchangers, and devices to control fluid pressure, flow, temperature, and cleanliness. Hydraulic System Monitoring Units (HSMU) control and monitor these systems, interfacing with the Onboard Maintenance System (OMS) for diagnostic and monitoring purposes.
The hydraulic systems on the A380 are controlled via the Hydraulic Control Panel on the overhead panel, allowing manual control of each pump and depressurization/re-pressurization of EDPs. The Hydraulic Maintenance Panel allows for manual control of the EMPs. System indications, including hydraulic fluid level, temperature, overheat messages, and valve statuses, are displayed on the ECAM System Display (SD), ensuring continuous monitoring and feedback to the flight crew.
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