Air Conditioning

Question 1

How are the zone temperatures individually controlled?

Answer 1

• Temperature regulation is controlled by 2 air conditioning system controllers.
• Temperature regulation is optimized via the hot air pressure regulating valve, and the trim air valves that add hot air, tapped upstream of the packs, to the mixing unit air.

Question 2

What controls the packs and TAVs?

Answer 2

Pack operation is controlled by air conditioning system controller signals.

Question 3

What happens to the system during engine start?

Answer 3

1. If the crossbleed valve is closed, the valve located on the staring engine side immediately closes, when the mode selector is set to IGN or CRANK.
2. If remains closed on the starting engine side (provided the crossbleed valve is closed) when:
   a. MASTER SW on
   b. Start valve is open
   c. N2 <50%
3. On the ground, reopening of the valves is delayed for 30secs to avoid a supplementary pack closure cycle during 2nd engine start.

Question 4

What happens when a duct overheat occurs?

Answer 4

• The FAULT light come son amber.
• ECAM caution, when duct overheat is detected.
• The fault circuit detects an overheat when the duct temperature reaches 80 degrees once.

Question 5

When does the Pack Ram Air Inlet Flap close?

Answer 5

T/O: takeoff power is set and the main landing gear struts are compressed.
LDG: as soon as the main landing gear struts are compressed, as long as speed is greater or equal to 70kts. They open 20sec after speed drops below 70kts.

Question 6

What 3 conditions could cause the Pack Flow to be Higher than the selected on the overhead panel?

Answer 6

• In single-pack operation
• When the APU is suppling bleed air
• When temperature cannot be satisfied

Question 7

The compartment temperature controllers can be set to what range of temps?

Answer 7

18 – 30 degrees Celsius (64 – 86 degrees Fahrenheit)

Question 8

What happens if an ACSC has a LANE failure?

Answer 8

No effect, as the second lane takes over.

Question 9

What happens if an ACSC has a double LANE failure?

Answer 9

Related pack is lost (ACSC1 – flight deck, ACSC 2 – cabin), Hot Air Pressure Regulating Valve and associated Trim Air Valves close.

Question 10

When does a Pack Overheat FAULT light, (on OHP) extinguish?

Answer 10

When the temperature drops < 70 degrees and the flight crew selects OFF.

Question 11

What happens when the Ram Air Pushbutton is selected ON?

Answer 11

If the DITCHING p/b, on the CABIN PRESS panel is in normal position:

• Ram Air Inlet opens
• If delta P is greater or equal to 1 PSI, no emergency Ram Air flow in (Closed)
• If delta P is less than 1 PSI, outflow valve opens to 50% when under automatic control. It does not automatically open when it is under manual control. Emergency RAM airflow is directly supplied to the mixer unit.

Question 12

What limitations apply to the opening of the Ram Air Valve?

Answer 12

Only open if differential pressure is lower than 1 PSI.

Question 13

The LO/ECON pack flow setting thresholds.

Answer 13

A320 LO: if the number of occupants is below 141.

A321 ECON: if the number of occupants is below 168.