A320 Air Conditioning Flashcards

1
Q

What automatically controls the air conditioning system?

A

2 Air Conditioning System Controllers (ACSC’s)

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2
Q

What does ACSC stand for?

A

Air conditioning system controller

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3
Q

What valve controls the flow of air to the packs?

A

The “Pack Flow Control Valve”

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4
Q

How many channels do the ACSC’s have?

A

2

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5
Q

What would happen if an ACSC completely fails?

A

The Hot Air Pressure Regulating Valve and the associated Trim Air valves would close automatically

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6
Q

What happens to the pack flow control valves when the engine mode selector is selected to IGN/START?

A

The pack control valves close automatically to lessen the demand on the pneumatic system in preparation for engine start. If after a short time the engines are not started, the pack flow control valves will automatically open.

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7
Q

What could cause a pack flow control valve to close automatically?

A

-Engine mode selector selected to IGN/START
-ACSC dual channel failure
-ENG FIRE pushbutton selected on the overhead panel
-Selecting the DITCHING pushbutton to “ON” on the overhead CABIN PRESS panel
-A pack overheat
-Lack of airflow. The valves are spring loaded to the closed position and if there’s insufficient air flow they close automatically

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8
Q

What will happen on the ground if the packs are selected on, but neither engines or APU are running?

A

The fault light will illuminate on the PACK 1/2 push buttons. This is because neither the APU nor engines are on, thus there’s nothing to provide bleed air to the packs. This means there’s no airflow through the pack flow control valves. Because the valves are spring loaded to the closed position and only airflow keeps them open, the valves will remain closed even if the PACK pb’s are pushed. When the PACK push buttons are selected on, the plane will sense a disagreement between the command position (open) and the actual position (closed) of the pack flow control valves, which is communicated to the pilots through a FAULT light.

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9
Q

What does a fault light on #2 mean

A

A disagreement between the selected and actual position of the pack flow control valve, a pack outlet overheat, or a compressor outlet overheat.

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10
Q

What does a FAULT light on #2 mean?

A

-A disagreement between the selected and actual positions of the pack flow control valves
-A compressor outlet overheat
-A Pack outlet overheat

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11
Q

What does the white “OFF” light mean on #2?

A

The Pack 1 pushbutton is selected off

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12
Q

What does a fault light on #3 mean?

A

-Overpressure downstream of the engine bleed valve
-Bleed overheat
-Wing or engine bleed leak (on associated side)
-Bleed valve not closed during engine start
-Bleed valve not closed with APU bleed pushbutton selected
-HP valve failed on the ground
-Single BTS failure or BTS disagree on the ground
-Dual BTS failure in flight or on the ground
-Fan Duct burst detected by the FADEC (Leap 1A engine only)

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13
Q

What does the “OFF” light in #3 mean?

A

Illuminates when the bleed valve, fan air valve, and HP valve have all closed

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14
Q

What does the fault light on #5 mean?

A

Indicates an APU leak is detected

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15
Q

What does the “ON” light on #5 mean?

A

Illuminates when the APU bleed PB is selected ON

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16
Q

With #6 selected to AUTO, when will the crossbleed valve be opened?

A

It opens if the APU bleed valve is open. It closes when the APU bleed valves are closed, or in the case of a wing, pylon, or APU leak.

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17
Q

What does the fault light on #9 mean?

A

Illuminates when a duct overheat is detected (88ºC or 190ºF). If this occurs the hot air pressure regulating valve and the trim air valves close automatically. The light will extinguish when the temp drops below 70ºC and the HOT AIR pushbutton is selected off.

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18
Q

Which valve is #4 and what position is it in?

A

It’s the pack flow control valve, and the valve is open.

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19
Q

When is #1 selected to low and to high?

A

It’s selected to low to accommodate light passenger loads and to high to accommodate high passenger loads or hot days.

20
Q

How much airflow do you get when #1 is selected to low, norm, or high?

A

Low = 80%
Norm = 100%
High = 120%

21
Q

With #1 selected to low, when may the aircraft give you normal flow instead?

A

When the plane determines that additional cooling is required

22
Q

When is a high flow rate automatically selected regardless of the position of #1?

A

When operating on a single pack and when the APU is providing bleed air

23
Q

How do the ACSC’s control the pack temperature?

A

By modulating the RAM AIR inlet flap, and the TURBINE BYPASS valve.

24
Q

What does the ram air inlet flap do?

A

It allows outside air to flow through a feat exchanger (kind of like a radiator in a car) to cool off hot bleed air from the engines/APU prior to entering the PACKS.

25
Q

When does the RAM AIR inlet flap automatically close on takeoff?

A

When takeoff power is set. They reopen automatically once airborne.

26
Q

When does the RAM AIR inlet valve close on landing?

A

It closes as soon as the main landing gear struts are compressed and will reopen 20 seconds after the speed drops below 70kts.

27
Q

What does closing the TURBINE BYPASS valve do?

A

It forces air through the air cycle machine, decreasing the PACK outlet temperature.

28
Q

What does opening the turbine bypass valve do?

A

It allows warm air to bypass the air cycle machine, increasing the PACK outlet temperature.

29
Q

What’s indicated by #5?

A

The air flow rate through the PACKs (Low, norm, or high)

30
Q

What’s indicated by #6?

A

The position of the turbine bypass valve. When it’s pointing at “H” the position of the valve is open, allowing warm air to bypass the air cycle machine. When “C” is pointed at, the turbine bypass valves is closed, forcing air through the air cycle machine.

31
Q

How is the temperature of each different aircraft zone controlled?

A

By adjusting the associated trim air valves, allowing varying amounts of warm air to be added to the cool pack air. This allows different zones to be cooled to different temperatures.

32
Q

How does air get into the mixing unit?

A

A few different ways. In normal operation air enters the mixing unit from the packs (conditioned air) and from the cabin fans (recirculated air from the cabin). On the ground the mixing unit can also receive air directly from the external low pressure air at the gate. Lastly air can enter the mixing unit from the ram air valve when its open.

33
Q

What does a FAULT light on #1 mean?

A

-Blowing pressure is low
-Duct overheat
-Computer power supply failure
-Smoke warning is activated

34
Q

What does the fault light on #2 mean?

A

-Extract pressure is low
-Computer power supply failure
-Smoke warning is activated

35
Q

What does pushing the #3 pb do?

A

It turns the cabin fans off.

36
Q

Can you use low pressure air at the same time as air from the packs?

A

No. It’s an aircraft limitation and cannot be done.

37
Q

How can you know if low pressure air is connected to the aircraft?

A

-Asking ground personnel
-Listening for airflow through the vents
-Checking for moderate temperatures on the COND page

38
Q

What does pushing the guarded RAM AIR pushbutton do?

A

It opens the ram air valve to allow for ventilation of an unpressurized aircraft. When the RAM AIR pb is selected on, the outflow valve opens to 50%, provided that its under automatic control and differential PSI is less than 1.

39
Q

Will the RAM AIR valve open if the DITCHING pb on the overhead panel is selected on?

A

No

40
Q

Where does air from the RAM AIR valve go?

A

It goes directly to the mixing unit, and then on to the three different zones.

41
Q

When will the hot air pressure regulating valve automatically close?

A

-The absence of hot bleed air (spring landed to close)
-Duct overheats
-Cockpit trim air valve failure
-Both cabin trim air valve failures

42
Q

Can the flight attendants adjust the temperature of the cabin air?

A

They have a flight attendant panel that allows them limited ability change the air temperature. They air able to adjust the temperature +/-2.5ºC from what the cockpit overhead panel is selected to.

43
Q

Is the aft cargo compartment air conditioned?

A

Yes

44
Q

How is the aft cargo air heated?

A

Cabin air is mixed with varying amount of hot bleed air by modulating the Cargo Trim Air valve.

45
Q

What happens if the aft cargo inlet temperature exceeds 70ºC? 88ºC?

A

At 70ºC the controller closes the cargo trim air valve. At 88ºC the controller closes the Cargo pressure regulating valve.

46
Q

In the event of a duct overheat, how can the aft cargo pressure regulating valve be reopened?

A

It can be reopened by pushing the HOT AIR pushbutton on the overhead panel once the temperature gets below 70ºC.