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A320 Notes > Hydraulics > Flashcards

Flashcards in Hydraulics Deck (55):
2

What is the function of the system accumulators?

An accumulator in each system helps to maintain a constant pressure by covering transient demands during normal operation.

3

When does the RAT extend automatically?

The RAT extends automatically if AC BUS 1 and AC BUS 2 are lost.

4

What is the normal pressure in the hydraulic system?

3000psi.

5

What is the function of the fire shutoff valves?

Each of the green and yellow system has a fire shutoff valve in its line upstream of its engine-driven-pump. The flight crew can close it by pushing the ENG1(2) FIRE pb.

6

How many hydraulic systems has the A320?

The aircraft has three hydraulic systems referred to as GREEN BLUE and YELLOW.

7

During start up when is the BLUE hydraulic system pressurized?

Automatically after first engine start.

8

What does the RAT MAN ON switch do?

Extends RAT pressurizes BLUE system does not start Emergency Generator.

9

What is the function of the Power Transfer Unit (PTU)?

The bidirectional PTU enables the yellow system to pressurize the green system and vice versa.

10

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.

11

Can you transfer hydraulic fluid between the hydraulic systems?

No hydraulic fluid cannot be transferred from one system to another.

12

The PTU start running if the differential pressure between the green and yellow hydaulic system is ...

>500psi.

13

What is the purpose of the leak measurement valves?

Each hydraulic system has a leak measurement valve upstream of the primary flight controls. These valves which measure the leakage in each circuit are closed by operation of the LEAK MEASUREMENT VALVES pushbutton switch on the maintenance panel.

14

Why are the hydraulic reservoirs pressurized with bleed air?

Normally HP bleed air from engine 1 pressurizes the hydraulic reservoirs automatically to maintain a high enough pressure to prevent their pumps from caviating.

15

What is the purpose of the RAM AIR TURBINE (RAT)?

A drop-out RAT coupled to a hydraulic pump allows the blue system to function if electrical power is lost or both engines fail. The RAT deploys automatically if AC BUS 1 and AC BUS 2 are lost and It can be deployed manually from the overhead panel. It can be stowed only when the aircraft is on the ground.

16

How many pumps are located within the YELLOW system?

Four elec pump engine pump PTU and hand pump.

17

What does the amber level indication mean on the hydraulic quantity indicator?

The warning level.

18

What is the function of the priority valves?

Priority valves cut off hydraulic power to heavy load users if hydraulic pressure in a system gets low.

19

ENG 1 (2) PUMP pb
(HYD Panel)


- ON
- OFF
- FAULT Light

On:
Pump is on when the engine is running.


OFF:
The pump is depressurized.


FAULT Light:
With ECAM caution if:
- Reservoir low level
- Reservoir overheat (stays on while condition lasts)
- Reservoir low air pressure
- Low pump pressure (inhibited on the ground, when the engine is stopped)

20

BLUE ELEC PUMP pb
(HYD Panel)

- AUTO
- OFF
- FAULT Light

AUTO:
If AC power is available, the electric pump operates:
- In flight
- On the ground, if one engine is running.

OFF:
The pump is de-energized.

FAULT Light:
With ECAM caution if:
- Reservoir low level
- Reservoir low air pressure
- Reservoir overheat (stays on while condition lasts)
- Pump low pressure (inhibited on the ground, when the engines are stopped)
- Pump overheat

21

YELLOW ELEC PUMP pb
(HYD Panel)

- ON
- OFF
- FAULT Light

(springloaded)

ON:
Electric pump is ON. If the electrical power supply is removed, the pump remains off when electrical power is applied again.

Off:
The pump is off. It comes on automatically during cargo door operation. This inhibits the operation of other yellow system functions (except alternate braking and engine 2 reverse).

FAULT Light:
With ECAM caution if:
- Reservoir low level
- Reservoir low air pressure
- Reservoir overheat (stays on while condition lasts)
- Pump low pressure
- Pump overheat

22

PTU pb
(HYD Panel)

- AUTO
- OFF
- FAULT Light

AUTO:
The power transfer unit is armed and both the Y and G electrohydraulic valves are open. PTU runs automatically when the differential pressure between the green and yellow systems is > 500 PSI.
Inhibited:
- during the first engine start, (split MASTER SW + parking break or NWS disconnected)
- during cargo door operation, and after that for 40 sec
Automatically tested during the second engine start.

OFF:
Both the green and the yellow PTU electrohydraulic valves close. Power
transfer stops.

FAULT Light:
With ECAM caution if:
- G or Y reservoir low air pressure
- G or Y reservoir low level
- G or Y reservoir overheat
(stays on as long as the overheat lasts).

23

RAT MAN ON pb
(HYD Panel)

The flight crew may extend the RAT at any time by pressing the RAT MAN ON pb.

24

Name several items that run from only the GREEN system?

- Landing Gear

- Normal Brakes

- Slats/Flaps

- Engine 1 Reverser

25

What is the function of they hydraulic priority valves?

Hydraulic power to the flaps, slats, landing gear, NWS, and emergency generator is cut off if the pressure drops below a predetermined value (High demand items)

26

What hydraulic system supplies nose wheel steering?

Yellow

27

When brake accumulator pressure is low, how is it recharged?

With the Yellow hydraulic system electric pump

28

With only Green hydraulic system pressure available, will both the flaps and slats operate?

Yes, at 1/2 speed

29

If NO hydraulic power is available can the THS be positioned?

No, the THS requires hydraulic power from the Green or Yellow systems

30

Which hydraulic systems provide pressure to the brakes?

- Normal Brakes: GREEN

- Alternate Brakes: YELLOW backed up by a hydraulic accumulator

31

If you lose Green hydraulic pressure, will you have auto brakes?

No, not with the alternate brake system

32

What does the BRAKES & ACCU PRESS triple indicator indicate?

- Yellow hydraulic pressure delivered to the left and right brakes

- Yellow system brake accumulator pressure

33

How do you perform the brake check during initial taxi?

Press the brake pedals to ensure the aircraft slows, and check the brake pressure on the triple indicator is zero, indicating the Green hydraulic system has taken over

34

Can the aircraft be flown with a loss of all hydraulic systems?

No, you must have at least one

35

What occurs when you pres the RAT MAN ON pushbutton?

The RAT extends providing pressure to the BLUE hydraulic pump

36

Does the PTU transfer hydraulic fluid?

No

37

How many hydraulic pumps are in the GREEN system?

- 1 Engine driven pump

- 1 PTU

38

How many hydraulic pumps are in the BLUE system?

- 1 Electric pump

- 1 RAT

39

How many hydraulic pumps are in the YELLOW system?

- 1 Engine driven pump

- 1 Electric pump

- 1 PTU

- 1 Hand Pump

40

What is normal system hydraulic pressure?

3000 psi +/-200

41

Does the RAT automatically deploy with the loss of BLUE hydraulic pressure?

No, it must be deployed manually by the RAT MAN ON pushbutton

42

What condition will cause the PTU to operate when the pushbutton is in AUTO?

A difference of 500 psi between the GREEN and YELLOW hydraulic systems

43

What is the purpose of the hand pump?

To provide Yellow hydraulic pressure for cargo door operation

44

How long does it take for the RAT to extend and provide power?

8 seconds (3 seconds for rat to extend, and 5 seconds to pressurize the Blue hydraulic system and power the EMER GEN)

45

When is the PTU inhibited?

- PTU pushbutton is OFF

- First Engine start

- Parking brake is ON and only one ENG MASTER switch is ON

- NWS in towing position and parking brake ON

- Cargo door operation (PTU is also inhibited for 40 seconds after the end of cargo door operation)

46

Name several items that run from only the YELLOW system?

- NWS

- Alternate Brakes

- Parking Brake

- Cargo Doors

- Engine 2 Reverser

47

If the ACCU PRESS indicator is low, what should you do?

Obtain ground clearance then turn ON the YELLOW ELEC PUMP to pressurize the accumulator

48

Does operating the cargo door run the PTU?

No, it is inhibited

49

Which systems are not inhibited during cargo door operation?

- Alternate Braking

- Engine 2 reverser

- NWS (if bypass pin not installed)

50

When does the BLUE ELEC PUMP operate?

- After the first engine is started

- If the BLUE PUMP OVRD pb on the MX Panel has been pressed with no engine running

51

If the "FAULT" light in the PTU pushbutton is ON, are there any other indications on the HYD Panel?

Yes, FAULT light illuminated in the respective ENG PUMP pushbutton

52

If the ECAM actions lead you to turn OFF the PTU for a Reservoir Overheat, will the FAULT light go out?

No, not until the overheat condition subsides

53

Can the YELLOW ELEC PUMP run the PTU?

Yes

54

What does an amber "FAULT" light in the PTU pushbutton indicate?

- Overtemp in Reservoir

- Low air pressure in the reservoir

- Low quantity in the reservoir

55

What does a "FAULT" light in the BLUE or YELLOW ELEC PUMP pushbutton indicate?

- Pump pressure low

- Overtemp in the reservoir

- Low air pressure in the reservoir

- Low quantity in the reservoir

- Overheat of pump

56

What is different about the deployment of the RAT from the HYD panel?

Blue HYD pressure only, no emergency generator