Hydraulic System DSC 29 Flashcards
What is the normal hydraulic system pressure for green, blue and yellow systems?
3000 psi
What system pressure is the blue system when powered by the RAT?
2500psi
How is the Green system pressurised?
A pump driven by engine 1
How is the Blue system pressurised?
- An electric pump
- A pump driven by the RAT (in an emergency)
How is the Yellow system pressurised?
- A pump driven by Engine 2
- An electric pump (for use on ground when engines are stopped)
- A hand pump to operate cargo doors when electrics are not available
What is the PTU?
A bidircectional power transfer unit.
It enables the yellow and green systems to pressurise each other
When will the PTU automatically activate?
- When differential pressure between G + Y >500psi
- during the second engine start, for the automatic test
When is the PTU inhibited?
During the first engine start
What is the drop out RAT coupled to?
A hydraulic pump
When will the RAT automatically deploy?
If AC bus1 and AC bus2 are both lost
Can the RAT be manually deplyed?
Yes, from the overhead panel
When can the RAT be stowed?
Only on the ground
What do priority valves do?
Cut off hydraulic power to heavy load users if hydraulic pressure in a system gets low eg NWS (YUD) Landing gear Slats and flaps Emer gen
What heavy load users does the priority valve in the green system cut off?
NWS (YUD)
Landing gear
Slats and flaps
What heavy load users does the priority valve in the Blue system cut off?
Emer Gen
Slats
What heavy load users does the priority valve in the Yellow system cut off?
Flaps
which systems have Fire Shut off valves?
Green and Yellow
Upstream of its engine driven pump
What is the purpose of the leak measurement valves?
Measure hydraulic leakage of each circuit
Where are the leak measurement valves located?
Each system has 1 LMV upstream of the Primary Flight Controls.
How can the Leak Measurement Valves be closed?
By operation of the LMV pushbutton on the maintenance panel
How are the hydraulic reservoirs normally pressurised?
Automatically, by HP bleed air from engine 1
If bleed air pressure for the hydraulic reservoirs is too low from where does the system take bleed air pressure?
From the crossbleed duct
Under what conditions would the HYD ENG pump FAULT light and ECAM appear?
- Reservoir level is Low
- Reservoir Overheats
- Reservoir air pressure is Low
- Pump Pressure is Low
When will the Fault light not go out after being selected OFF?
During an overheat, while the overheat still exists
