Pneumatic

Question 1

High Pressure Air Sources

Answer 1

‐ Engine bleed systems
‐ APU load compressor
‐ HP ground connection

Question 2

Normal source of bleed air

Answer 2

intermediate pressure stage (IP) of engine’s high-pressure (HP) compressor

Question 3

APU BLEED pb-sw is pressed

Answer 3

• if the APU speed is above 95 % the crossbleed valve opens and the engine bleed closes automatically
• automatically closes in the case of APU leak, left wing leak, or pylon 1 leak

Question 4

How many motors operate the crossbleed valve?

Answer 4

Two electric motors, one for automatic mode and one for manual mode

Question 5

Normal bleed air temperature

Answer 5

approximately 200 °C

Question 6

Purpose of Emergency Ram Air Valve

Answer 6

• provides ventilation to the cockpit and cabin to remove smoke, or if both packs fail
• With Ram Air pb ON outflow valve opens about 50 %, provided that it is under automatic control and ΔP is less than 1 PSI
• If ΔP is greater than 1 PSI, the check valve located downstream the ram air door will not open

Question 7

When does RAM AIR inlet flap close?

Answer 7

During Takeoff: when takeoff power is set, and the main landing gear struts are compressed

During Landing: closes as soon as the main landing gear struts are compressed, as long as speed is at or above 70 kt
It opens 20 s after the speed drops below 70 kt

Question 8

When is PACK FLOW automatically set to HI?

Answer 8

‐ In single-pack operation,

‐ When the APU is supplying bleed air

Question 9

What are the functions of the pressurization system?

Answer 9

‐ Ground function : Fully opens the outflow valve on ground

‐ Prepressurization : During takeoff, increases cabin pressure to avoid a surge in cabin pressure during rotation

‐ Pressurization in flight : Adjusts cabin altitude, and rate of change to provide passengers with a comfortable flight

‐ Depressurization : After touchdown, gradually releases residual cabin overpressure before the ground function fully opens the outflow valve.

Question 10

How many motors drive the outflow valve?

Answer 10

• one of the three independent electric motors may power the outflow valve (two automatic and one manual)
• two cabin pressure controllers operate its respective motor

Question 11

When do the two Cabin Pressure Controllers (CPC) switch control?

Answer 11

An automatic transfer occurs:
• 70 s after each landing
• If the operating system fails

Question 12

What does the Ditching pb control?

Answer 12

Sends a close signal to:

the outflow valve
the emergency ram air inlet
the avionics ventilation inlet and extract valves
the pack flow control valves
and the FWD cargo outlet isolation valve

Question 13

When does the HOT-AIR PRESSURE REGULATING VALVE automatically close?

Answer 13

The valve closes automatically, if:
‐ The duct overheats, or
‐ The cockpit trim air valve fails, or
‐ Both cabin trim air valves fail

Question 14

What does the Cabin Pressure Controller use to calculate a pressure schedule?

Answer 14

• The controller normally uses the landing elevation and the QNH from the FMGC, and the pressure altitude from ADIRS
• If FMGC data are not available, the controller uses the captain BARO Reference from the ADIRS and the LDG ELEV selection