How many hydraulic systems?
3 systems Left, right, center
Independent 5000psi systems
A single system provides sufficient power for full aircraft control
Each system has a dedicated reservoir pressurized by pump outlet pressure
Each system has shutoff valves or isolation valves (center system) to be used during non normal operations
Which systems receive hydraulic power?
Primary hydraulic pumps
Engine driven by respective left or right engine
EMPs (electric motor-drive hydraulic pumps)
Employed during high load phases of flight and also to provide system redundancy
Center system EMPs
Designated C1 and C2
Operate as primary or demand pumps. Alternate as primary
Pump acting as primary will operate continuously
Left hydraulic system powers:
Right hydraulic system powers:
Pulling engine fire switch does what with respect to hydraulics?
Closes the engine driven pump hydraulic shutoff valve
Depressurizes the engine driven pump
Center hydraulic systems powers the following:
RAT (Ram Air Turbine)
Provides backup hydraulic power to center system
Located in a compartment after of the right main landing gear
Can be deployed automatically or manually
Provides 5,000 psi power to center hydraulic system
RAT will auto deploy when:
Primary pump FAULT light, or center system C1 / C2 fault light, illuminates:
Low pump pressure
Excessive pump fluid temperature
Pump is selected off
With AUTO selected, L/R hydraulic demand pumps operates when:
C1 / C2 demand pumps operates under the following conditions in Auto:
RAT “press” light illuminates when:
RAT is deployed
Center system hydraulic pressure greater than 3,000 psi
RAT “unlocked” light (or EICAS “RAT UNLOCKED “)
RAT is not in stowed position
Center system isolation function uses:
