Hydraulics

Question 1

Which systems have an accumulator?

Answer 1

All three!

Question 2

What is the hydraulic system pressure normally?
And when supplied by the RAT?

Answer 2

3000psi +/- 50psi
2500psi if supplied by RAT

Question 3

When does the PTU kick in?

Answer 3

With a difference of 500psi between Green/Yellow system

Question 4

What are priority valves used for in the hydraulic system?

Answer 4

To cut off hydraulic power to heavy load users if hydraulic pressure in a system gets low to protect flight controls
e.g. landing gear, slats, flaps, emergency gen

Question 5

Which are the heavy load users that the priority system can isolate?

Answer 5

Green: Landing Gear, Slats + Flaps
Blue: Emer Gen, Slats
Yellow: Flaps

Question 6

On the HYD SD page, what does the circle represent towards the bottom of the Green and Yellow systems?

Answer 6

The hydraulic fire shut off valve (controlled through FIRE PB)

Question 7

Main systems powered by the Green system?

Answer 7

Landing Gear
Slats and Flaps
Rev Eng 1
Normal Brakes
Flight Controls

Question 8

Main systems powered by the Yellow system?

Answer 8

Flaps
Nose Wheel Steering
Rev Eng 2
Alternate Braking
Parking Brake
Flight Controls

Question 9

Main systems powered by the Blue system?

Answer 9

Emer Gen
Slats
Flight Controls

Question 10

In the event of HYD LO AIR PR, why does ECAM instruct you to turn pump back on during approach?

Answer 10

Pump cavitation less likely at lower levels where air is more dense, thus may be able to recover hyd system

Question 11

How does PTU function during engine start procedure?

Answer 11

PTU inhibited during first engine start (and cargo door operation); self tests during 2nd engine start

Question 12

What landing capability will you have with single and dual hydraulic failure?

Answer 12

Single - CAT 3 SINGLE
Dual - CAT 1

Question 13

What are the consequences of a single hydraulic failure?

Answer 13

CAT 3 SINGLE
Normal Law
AP and A/THR available

Question 14

What are the consequences of all dual hydraulic failures?

Answer 14

CAT 1
Lose AP1 + AP2
Gravity gear extension (get early landing clearance as gear staying down - 2.8 times fuel burn)
Red LAND ASAP

Question 15

G + Y HYD Failure.
Key points.

Answer 15

Look at ECAM SUMMARY!

Landing Distance

Alternate -> Direct Law

No flaps. Slats slow.

Both reversers lost.

NWS lost.

Brakes- Y accumulator only; 7 applications

CONF 3 landing only.

Gear down (gravity gear extn) when in CONF3 and at VAPP - No stabiliser; auto trim through elevators; when gear down, lose auto trim, elevator position memorised; says USE MAN PITCH TRIM - ignore this!

If flaps jammed close to 0, tail strike risk.

Plus generic dual hyd fail stuff:
CAT 1
Lose AP1 + AP2
Gravity gear extension
Red LAND ASAP

Question 16

G + B HYD Failure.
Key points.

Answer 16

Look at ECAM SUMMARY!

Controllability

Alternate -> Direct Law

No slats. Flaps slow.

REV ENG 1 lost.

No aileron, one elevator.

Alternate braking with A/S.

CONF 3 landing only.

Extend gear (gravity gear extn) at 200kts - revert to Direct Law sooner for better pitch control.

Plus generic dual hyd fail stuff:
CAT 1
Lose AP1 + AP2
Gravity gear extension
Red LAND ASAP

Question 17

B + Y HYD Failure.
Key points.

Answer 17

Look at ECAM SUMMARY!

Easy!

Normal Law.

Land either config.

Slats and Flaps slow.

REV ENG 2 lost.

NWS lost.

Normal brakes.

Gravity gear extension to protect remaining hyd system.

Plus generic dual hyd fail stuff:
CAT 1
Lose AP1 + AP2
Gravity gear extension
Red LAND ASAP