Pressurisation DSC 21

Question 1

System consists of….

Answer 1

2 Cabin Pressurisation Controllers (CPC)
1 Residual Pressure Control Unit (RPCU)
1 Outflow valve (with an actuator that incorporates 3 motors)
1 Control Panel
2 Safety Valves

Question 2

The CPC’s receive info from…?

Answer 2

ADIRS
FMGC
EIU
LGCIU

Question 3

When the system is in auto or semi-auto, 1 CPC is active and the other is on standby. T/F?

Answer 3

True

Question 4

Where is the outflow valve situated?

Answer 4

RHS fuselage, behind aft cargo and below flotation line

Question 5

When the RAM AIR pb is ON and ∆P is <1 psi what position does the system drive the outflow valve to if its under automatic control?

Answer 5

50% OPEN

Question 6

When the RAM AIR pb is ON and ∆P is <1 psi what position does the system drive the outflow valve to if its under manual control?

Answer 6

The outflow valve does not automatically open,

even if the ∆P is <1 psi

Question 7

At what pressure do the pneumatic safety valves activate?

Answer 7

> 8.6psi (can be a range of 8.2 - 8.9 due to accuracy of ∆P in MAN mode)

<1psi

Question 8

Where are the safety valves located?

Answer 8

Rear pressure bulkhead,

above the flotation line

Question 9

What does the Residual Pressure Control Unit (RPCU) do?

Answer 9

Automatically depressurises the aircraft in case of abnormal residual pressure on the ground.

Question 10

When does the Residual Pressure Control Unit (RPCU) automatically open the outflow valve?

Answer 10

The aircraft is on the ground, and
The outflow valve is not fully open, and
Both CPC’s are failed, or manual mode is selected, and
All engines shutdown, or ADIRS indicate <100kts

Question 11

How many CPC’s operate at the same time?

Answer 11

only 1

Question 12

When does automatic change over of the CPC’s occur?

Answer 12

• 70secs after each landing

- If the operating CPC fails

Question 13

Where does the CPC get landing elevation, QNH and Pressure altitude info from?

Answer 13

FMGC -landing elevation, QNH

ADIRS -Pressure altitude

Question 14

If FMGC data is not available to the CPC then where does the CPC get BARO and Landing elevation info from?

Answer 14

ADIRS -BARO

LDG ELEV knob -Landing elevation

Question 15

When is the outflow valve fully open?

Answer 15

Before take-off and

55 sec after landing

Question 16

At touchdown, any remaining pressure is released at. ______ft/min

Answer 16

500 ft/min

Question 17

To avoid pressure surge at rotation the controller pre-pressurises the aircraft at a rate of _____ft/min, until the ∆P reaches _____psi

Answer 17

400 ft/min

0.1 psi

Question 18

During descent the controller maintains a cabin rate of descent such that the cabin pressure is equal to the landing field pressure +_____psi shortly before landing.

Answer 18

+1 psi

Question 19

What is the maximum descent rate?/

Answer 19

750 ft/min

Question 20

If the aircraft does not climb after take-off what does the abort mode do?

Answer 20

Prevents the cabin altitude from climbing.

Question 21

What is cabin altitude set to after an abort?

Answer 21

take-off altitude +1psi

Question 22

What happens when the mode selector is selected to MAN?

Answer 22

Power is cut to the automatic motors.

MAN motor can control the outflow valve

Question 23

What does the MAN V/S CTL switch UP position do?

Answer 23

Opens the outflow valve

Increases the Cabin Altitude

Question 24

Due to the slow operation of the outflow valve in manual mode and the limited resolution of the position on ECAM, how long can the visual ECAM take to indicate the change in position?

Answer 24

up to 5secs

Question 25

In MAN operation, does the outflow valve open automatically at touchdown?

Answer 25

NO!

Question 26

What does the DITCHING pb on the CABIN PRESS control panel do?

Answer 26

Closes all hatches below the flotation line:
Outflow valve
Emergency RAM AIR inlet
Avionics vent inlet
Extract valves
Pack flow control valves

Question 27

How can the flight crew select the other CPC?

Answer 27

By switching the MODE SEL to MAN, for at least 10sec, then returning it to AUTO

Question 28

When will the MODE SEL FAULT light illuminate?

Answer 28

When BOTH automatic systems are faulty

Question 29

If in MAN mode and the DITCHING pb is switched ON, will the outflow valve close automatically?

Answer 29

NO!

Question 30

When will VS FT/MIN appear in amber?

Answer 30

VS >= 2000 fpm

Question 31

When will VS FT/MIN pulse green?

Answer 31

VS > 1800fpm

resets at 1600 fpm

Question 32

When will ∆P appear in amber?

Answer 32

∆P <= -0.4 psi, or

∆P >= 8.5 psi

Question 33

When will ∆P appear pulse green?

Answer 33

∆P > 1.5 psi during flight phase 7 (800ft to touchdown)

resets at 1 psi

Question 34

When will the CAB ALT appear in Red?

Answer 34

> 9550 ft

Question 35

When will the CAB ALT pulse green?

Answer 35

At or above 8800 ft

resets at 8600 ft

Question 36

SAFETY in amber on the CAB PRESS SD page means?

Answer 36

either safety valve is not closed

Question 37

When would the outflow valve position become amber?

Answer 37

Valve opens > 95% during flight