A320 Lounge Hydraulics 1 Flashcards
Which hydraulic systems have their own reservoir?
All of them
Which hydraulic reservoir is biggest?
Green 14.5 litres
Yellow 12.5 litres
Blue 6.5 litres
Which hydraulic systems are powered by engine driven pumps?
Green and Yellow
What is the normal pressure in the hydraulic system?
3000psi
Which hydraulic systems are normally powered by electric pumps?
Blue
The yellow system also has an electric pump if selected by pilots or if cargo door opened
Which hydraulic systems are supplied with pressure by the RAT?
Blue
How much pressure is supplied by the RAT?
2500psi
What is the function of the PTU?
Allows green system to pressurise yellow system, or the opposite, if there is a pressure deficit.
Fluid is not transferred
Which hydraulic systems have fire shutoff valves?
The green and the yellow systems.
They’re fitted close to the accessory gearbox in the engine, so if there is an engine fire, it prevents the hydraulic fluid, which is flammable, being sent into the engine fire
How are the hydraulic fire shutoff valves activated?
By the engine fire push button
Which part of the engine is the engine driven pump connected to?
N2
When does the blue electric pump start?
When the first engine is started
When is the yellow electric driven pump activated?
Manually, when we press the yellow hydraulic push button, or when ground crew operate cargo doors
Which hydraulic system has a hand pump?
Yellow
When is the hand pump used?
When the yellow electric pump is inop, enabling ground crew to manually pump in order to open cargo doors
When does the blue electric pump turn off?
When the last engine is turned off
When will the engine driven pump sensor get triggered?
Below 1750psi
When will the electrically driven pump sensor get triggered?
Below 1450psi
(For blue or for yellow)
What does the accumulator do?
Store fluid and store pressure, so that when the pressure isn’t quite 3000psi, the energy in the fluid helps to regulate the natural peaks and troughs and keep system at 3000psi
When is PTU active?
If difference in pressure is greater than 500psi
When is PTU tested?
Second engine start
When is PTU inhibited?
On ground during 1st engine start
NWS DISC amber
On ground, if parking brake off if engine masters alt position (on/off) - if the master switches are in the same position, it is only active with the difference of 500psi. If the masters are in opposite positions (eg single engine taxi), the PTU inhibited only if the parking brake is on
Why is PTU inhibited when NWS DISC amber present?
We don’t want to accidentally pressurise the NWS and potentially damage towing equipment
Why do the pump outlet pressure sensor and system pressure sensor trigger at different times?
Because pressure sensor is downstream of the PTU, helping identify if the system is still pressurised via the PTU when a pump failure occurs
Which triggers at a higher psi, pump outlet pressure sensor or system pressure sensor?
Engine driven pumps looking for 1750psi, whereas system pump looking for 1450psi
