HYDRAULICS Flashcards
What’s the function of the accumulators?
Helps to maintain a constant pressure by covering transient demands during normal operation
When does the RAT extend automatically?
The RAT extends automatically if AC BUS 1 and AC BUS 2 are lost
What’s the normal pressure in the hydraulic system?
3000 psi
What’s the function of the fire shutoff valves in the hydraulic system ?
To shut off hydraulic fluid to the engine driven pumps
Which hydraulic systems have fire shutoff valves?
Green and Yellow systems
How can the crew close the hydraulic fire shutoff valves?
By pushing the ENG 1(2) FIRE PB
How many hydraulic systems does the A320 have and what are their colors?
3 and they are colored GREEN-BLUE-YELLOW
What is the pressure output from the RAT in the hydraulic system?
2500 psi
What happens when the RAT MAN ON switch on the hydraulic overhead panel is pushed?
What doesn’t happen?
It extends the RAT, pressurizes the BLUE system. It does not start the emergency generator
What is the function of the PTU in the hydraulic system?
It’s function is for the YELLOW system to pressurize the GREEN system and vice versa
When you get a “G RSVR OVHT” message, why does the ECAM procedure ask you to switch off the PTU first?
To prevent the PTU from pressurizing the GREEN system
When will the PTU in the hydraulic system start operating?
When the pressure difference between the GREEN and YELLOW system is greater than 500 psi
What is the purpose of the leak measurement valves?
To measure leakage in each circuit
Why are the hydraulic reservoirs pressureized with bleed air?
To prevent cavitation by maintaining a high enough pressure
From where is the bleed air taken that’s used to pressurize the hydraulic reservoirs?
Normally HP bleed air from ENG 1
How many pumps are there that can pressurize the YELLOW hydraulic system?
4
1. Engine driven pump
2. Electrical pump
3. PTU
4. Hand pump
What does the amber level indication mean on the hydraulic quantity indicator?
It’s the warning level
What are the function of the priority valves in the hydraulic system?
To cut off hyraulic power to heavy load users if pressure in a system is low. This is done to maintain pressure to the essential flight controls
What is a LAF in the hydraulic system, and with is it’s function?
Which hydraulic systems has this function?
LAF = Load Alleviation Function Accumulators
It’s function is to maintain operation of ailerons and spoilers during rapid operation in for example turbulence.
GREEN and YELLOW system has this function
Ailerons and spoilers 4+5 deflects upwards to reduce the stress on the wing root
Spoilers augments the ailerons in gusty conditions
Name a few items that is pressurized by the GREEN hydraulic system
NWS
Landing gear
Normal brakes
ENG 1 Reversers
Spoilers 1+5
L elevator
Flaps/slats
Rudder
L/R aileron
Stabilizer
Yaw damp
Name a few items that is pressurized by the BLUE hydraulic system
Emergency generator
Spoiler nr 3
Slats
Rudder
L/R aileron
L/R elevator
Name a few items that is pressurized by the YELLOW hydraulic system
Reverser ENG 2
Flaps
Rudder
Alternate/parking brake
R elevator
Spoilers 2+4
Stabilizer
Yaw damper
What hydraulic system supplies nose wheel steering (NWS)?
YELLOW
With only GREEN hydraulic system pressure, will both flaps and slats operate?
Yes, but at half speed
Which hydraulic system provides pressure to the Normal Brake System?
The GREEN system
What does the BRAKES & ACCU PRESS triple indicator give information about?
YELLOW pressure to the left and right brakes by the alternate brake system and the YELLOW brake accumulator pressure
Can the PTU in the hydraulic system transfer any fluid?
No, can only provide pressure
How many pumps are there in the BLUE hydraulic system?
2
1. Electric pump
2. RAT
What fluctuations of the hydraulic pressure is acceptable for it to still be in the normal range?
+/- 200 psi
What is the purpose of the YELLOW hydraulic hand pump?
To provide pressure for cargo door operation
When would the PTU in the hydraulic system be inhibited?
- PTU pushbutton is OFF
- First engine start
- During cargo door operation and 40 sec after cargo door ops
- NWS in towing position and parking brake ON
- Parking brake ON and only one ENG MASTER switch is ON
What would cause a FAULT light in the hydraulic PTU pushbutton switch?
LOW QUANTITY LEVEL
LOW AIR PRESSURE
OVERHEAT in the GREEN or YELLOW systems
Does operating the cargo doors run the hydraulic PTU?
No
What is a good way to charge the YELLOW alternate brake system?
By using the cargo door as the PTU wouldn’t be activated then
Why is it a bad idea to set and release the parking brake too many times?
The accumulator pressure in the YELLOW ALT/PARK BRAKE system will decrease
If the ECAM actions tells you to turn the PTU off for a hydraulic reservoir overheat, will the FAULT light in the pushbutton go out?
No, it stays illuminated for as long as the overheat condition exists
What happens when the cargo doors are operated with engines off?
The YELLOW electric pump starts operating
What is considered LOW PRESSURE in the hydraulic system?
Below 1450 psi
In what 3 ways can the RAT be deployed?
Loss of AC BUS 1&2
RAT MAN ON pb (no emergency gen ON)
MAN ON on EMER ELEC PWR 1
During start up, when is the BLUE hydraulic system pressurized?
Automatically after first engine start
If NO hydraulic power is available, can the THS be positioned?
No, it needs power from the GREEN or YELLOW system
If you loose the GREEN hydraulic pressure, will you still have AUTO BRAKES?
No, the alternate brake system doesn’t provide auto brakes
What do you check for when doing a brake check during intial taxi?
That the brake pressure on the triple indicator is zero. This indicates that the GREEN NORMAL BRAKE system is operational
Can the aircraft be flown with loss of all hydraulic pressure?
No, one system must be operational
Does the RAT deploy automatically with loss of BLUE hydraulic pressure?
No, the RAT MAN ON pb must be used
How long does it take for the RAT to extend and starting to provide power?
8 seconds in total
3 seconds for deployment and 5 seconds to start pressurizing
If the FAULT light in the hydraulic PTU pushbutton is illuminated, are there any other indications on the hydraulic overhead panel?
A FAULT light will be illuminated in the respective ENG PUMP pushbutton
What does a FAULT light in the BLUE or YELLOW hydraulic pushbutton indicate?
- Pump output pressure low
- Overtemp in the reservoir
- Low air pressure
- Low fluid quantity
- Pump overheat
What does a FAULT in the GREEN hydraulic pump pushbutton indicate?
What is different compared to the BLUE and YELLOW systems?
Same as for the BLUE and YELLOW with the difference that it’s not illuminated for PUMP OVERHEAT as the GREEN system doesn’t have an electrical pump
Can the green HYD system be pressurized on the ground with engines shut down?
Yes, by using the Yellow HYD systems power via the PTU
If ENG 1 bleed air pressure is too low, how can the HYD system be pressurized?
From ENG 2 via a cross bleed duct
What is the total capacity in liters of the BLUE HYD SYSTEM?
6.5 liters
What is the total capacity in liters of YELLOW HYD SYSTEM?
12.5 liters
What is the total capacity in liters of the GREEN HYD SYSTEM?
14.5 liters
What is the LOW LEVEL WARN in liters of the BLUE HYD SYSTEM?
2.4 liters
What is the LOW LEVEL WARN in liters of the YELLOW HYD SYSTEM?
3.5 liters
What is the LOW LEVEL WARN in liters of the GREEN HYD SYSTEM?
3.5 liters
What is the NORM FILLING range in liters of the BLUE HYD SYSTEM?
1.5 liters
What is the NORM FILLING range in liters of the YELLOW HYD SYSTEM?
2.5 liters
What is the NORM FILLING range in liters of the GREEN HYD SYSTEM?
2.5 liters
