Hydraulics

Question 1

How many hydraulic systems does the A320 have and what are they?

Answer 1

• 3 systems
• green blue and yellow

Question 2

What is the hydraulic system pressure?

Answer 2

3000 psi

Question 3

How is normal hydraulic pressure produced

Answer 3

Engine driven hydraulic pumps

Question 4

How can back up hydraulic pressure be produced?

Answer 4

• electrically driven hydraulic pressure pumps (Y/B only)
• Power transfer unit (PTU) (G/Y only)
• ram at turbine (RAT) (blue)
• hand pump (yellow)

Question 5

How many accumulators are installed and what are they used for?

Answer 5

• 3 accumulators one for each hydraulic system
• They help maintain a constant pressure during transient demands

Question 6

How many engine driven hydraulic pumps are there?

Answer 6

• 2
• One for the green hydraulic system
• One for the yellow hydraulic system

Question 7

How many electric driven hydraulic pumps are there?

Answer 7

• 2
• One for the blue hydraulic
• One for the yellow hydraulic system

Question 8

The flaps are controlled by which hydraulic system?

Answer 8

Yellow and green

Question 9

Nosewheel steering and landing gear are controlled by which hydraulic system

Answer 9

Green

Question 10

The slats are controlled by which hydraulic system?

Answer 10

Blue and green

Question 11

The parking brake is controlled by which hydraulic system?

Answer 11

Yellow 

Question 12

The cargo doors are controlled by which hydraulic system?

Answer 12

Yellow

Question 13

The emergency generator is powered by which hydraulic system?

Answer 13

Blue

Question 14

How is the blue hydraulic system pressurized?

Answer 14

Single electric pump when engine is running

Question 15

If the blue hydraulic electric pump fails, how can the blue hydraulic system be pressurized?

Answer 15

Via the ram air turbine (RAT)

Question 16

Why are the hydraulic reservoirs pressurized?

Answer 16

To prevent pump cavitation

Question 17

If the yellow engine driven pump fails, what happens to the electric pump

Answer 17

It does not automatically activate. Pilots need to push the yellow electric pump on.

Question 18

When does the yellow electric pump automatically operate?

Answer 18

When the cargo doors are operated

Question 19

When does the blue electric pump operate?

Answer 19

• with AC power available
• On the ground with one engine running
• Continuously, in-flight, even if both engines are shut down

Question 20

When does the PTU activate?

Answer 20

Automatically, if a pressure difference of more than 500 psi exists between G and Y hydraulic systems.

Question 21

Does the PTU transfer hydraulic fluid?

Answer 21

No, it only transfers pressure but not hydraulic fluid

Question 22

When does the RAT automatically deploy?

Answer 22

• when AC buses 1 and 2 fail

Question 23

Which systems does the RAT pressurize?

Answer 23

• Blue hydraulic system
• Emergency generator

Question 24

If you press the RAT MAN ON pb on the hydraulic overhead panel what happens?

Answer 24

• RAT deploys
• B hydraulic system is powered
• The emergency generator is not powered

Question 25

If the MAN ON pb on the EMER ELEC PWR panel is pushed what happens?

Answer 25

- RAT deploys - B hydraulic system is pressurized - Emergency generator is powered