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Flashcards in Air Conditioning Deck (13)
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How are the zone temperatures individually controlled?

- 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 air that leaves the mixing unit.


What controls the packs and TAVs?

(MSN dependant)
Old system:
Packs - Pack controllers (2)
TAVs - Zone controller (1)

New system:
Packs - ACSC
(2 ACSC's)

ACSC 1 controls the cockpit
ACSC 2 controls the Fwd & Aft cabin


What happens to the system during engine start?

If crossed valve is closed, the pack flow control valve is shut from IGN/Start to 30s after engine start.

1. If the crossbleed valve is closed, the pack valve will close when the mode selector is set to IGN or CRANK.
2. The pack valve remains closed on the starting engine side (provided the crossbleed valve is closed) when:
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.


a) What happens when a duct overheat occurs?

b) When does a HOT AIR pb FAULT light, (on OHP) extinguish?

- The FAULT light comes on amber.
- ECAM caution, when duct overheat is detected.
- The fault circuit detects an overheat when the duct temperature reaches :
88 degrees once.
80 degrees four times.

Hot air Valves & Trim air valves close.

b) The FAULT light goes off when the temperature drops below 70 degrees AND the flight crew selected OFF.


When does the Pack Ram Air Inlet Flap close?

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.


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

- In single-pack operation [HI]
- When the APU is suppling bleed air [HI]
- When temperature cannot be satisfied [Normal]


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

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


What happens if an ACSC has a LANE failure?

No effect, as the second lane takes over.


What happens if an ACSC has a double LANE failure?

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

ACSC 1 controls:
Hot Air Pressure Regulating valve
Cockpit Trim Air Valve

ACSC 2 controls:
FWD Cabin Trim Air Valve
AFT Cabin Trim Air Valve


a) When does a Pack pb FAULT light, (on OHP) occur?

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

Valve position disagree
Pack outlet temperature exceedance.

Threshold temperatures for a pack overheat is MSN dependant AND differ from the overheat-related figures associated with a HOT AIR FAULT.

ACSC Aircraft:
Alert triggers when compressor outlet temp rises above 260 Celsius.

Pack/Zone Controller Aircraft:
Alert triggers when compressor outlet temp rises above 260 Celsius.
Additionally, the alert triggers when compressor outlet temp rises above 230 Celsius FOUR times during a flight.
Pack outlet temperature rises above 95 celsius.

b) When the overheat disappears.


What happens when the Ram Air Pushbutton is selected ON?

Emergency Ram air init ventilates the cockpit and cabin to remove smoke OR if both packs fail.
Providing the DITCHING p/b, on the CABIN PRESS panel is in normal position:
- Ram Air Inlet opens
- If delta P (inside pressure vs outside pressure) 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.


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

Only open if differential pressure is lower than 1 PSI.


The LO/ECON pack flow setting thresholds.

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

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