Air Conditioning Flashcards
How many air conditioning zones are there?
3
What is an ACSC and how many are installed?
Air Conditioning System Controller.
2 installed
What is controlled by the respective ACSC?
ACSC 1: Cockpit zone and pack 1
ACSC 2: 2 cabin zones and pack 2
What are the main components of the Pack?
Primary heat exchanger
Main heat exchanger
Air Cycle Machine
How are the heat exchangers in the packs cooled?
Ram air
How is temperature of the pack regulated?
Pack bypass valve modulates temp by adding hot air tapped upstream of compressor to the ACM turbine exhaust. Also regulated by modulating the ram air inlet flap.
When is the pack flow control valve automatically closed?
- Low bleed pressure
- Pack overheat
- Engine start
- Engine fire pushbutton
- Ditching pushbutton
What are the possible inputs to the mixer units?
- Conditioned air from packs
- Recirculated cabin air from the cabin fans
- LP ground connection conditioned air
- Emergency ram air
How can the Hot Air PRV be controlled from the cockpit?
Using the HOT AIR pushbutton.
How is the Hot Air PRV controlled?
By ACSC 1
When will the Hot Air PRV close?
- Duct overheat
- Cockpit trim air valve fails
- Both cabin trim air valves fail
When is the Ram Air flap closed?
- When T/O power is set
- On landing when struts are compressed >70kts (opens after 20 seconds)
Which output temperature is produced by the packs?
Both pack will produce the lowest of the demanded temperatures.
When will the packs revert to high flow regardless of switch position?
- APU supplying the packs
- Single pack operations
What happens in case of a seized ACM compressor or turbine?
Pack reverts to heat exchanger mode.
- Uses primary heat exchanger only
- Reduced pack flow
When does the pack flow control valve open again following engine start?
After 30(60 NEO)seconds provided:
- Start valve closed
- N2 > 50%
What is the significance of a Pack FAULT light?
- Pack flow control valve disagree
- Compressor outlet overheat
- Pack outlet overheat
Pressing the RAM AIR pushbutton, when will the ram air inlet open?
Opens if:
- Ditching pushbutton OFF
- Cabin pressure diff <1psi
What cabin altitude will trigger EXCESS CABIN ALT ECAM?
> 9550’
When will the safety valves open?
> 8,6 psi
< 1 psi
How many motors drive the outflow valve?
3
How many Cabin Pressure Controllers are there?
2
What causes automatic changeover of CPC?
- Failure
- 70 sec after each landing
What happens when pressing the Ditching pushbutton?
Provided to pressurisation mode is AUTO:
- Outflow valve closes
- Avionics inlet/outlet valves close
- Emergency ram air inlet closes
- Pack flow control valve closes
What happens to the pressurisation on T/O?
Pre-Pressurisation when T/L set for T/O:
- Cabin climbs at 400’/min to 0,1 psi
When is the outflow valve opened and any residual pressure released?
55 seconds after landing
What is the max cabin altitude and pressure during cruise?
Approximately 8000’ and 8,06psi
Can the CPC be manually changed?
Yes. By selecting manual for 10 sec, then re-select auto.
When are the batteries ventilated?
Only in flight
How are the lavatories and galleys ventilated?
By an electric fan exhausting the air overboard
When do the avionics ventilation fans run?
Continuously when power is available
When would the Avionics Equipment Ventilation be in the open circuit mode?
On the ground with skin temp above threshold ( >9-12°C )
When would the Avionics Equipment Ventilation be in the closed circuit mode?
- On the ground with skin temp below threshold (<9-12°C)
- T/L set for takeoff
- In flight with skin temp below threshold ( <32-35°C )
What is the main difference between closed circuit and open circuit?
In closed circuit, the skin heat exchanger is used.
- Inlet and exhaust valves are closed
What happens when pressing OVRD in case of blower FAULT?
- Closed circuit configuration
- Blower stops
- Air conditioning inlet valve opens
How is smoke configuration set on the Avionics Equipment Ventilation system?
Pressing OVRD on both blower and extract fan pushbuttons
What happens in smoke configuration?
- Air conditioning inlet valve opens
- Blower fan stops
- All other valves close
- Air exhausted overboard through small flap in exhaust valve.
Which two pack temperatures are displayed on the ECAM bleed page?
Compressor outlet (lower) and Pack outlet (upper)
Is there any change in operation with the failure of one lane on one ACSC?
No effect
If both lanes fail on one ACSC, can the other ACSC take control of the affected pack?
No. Pack is lost.
At what cabin altitude will the signs automatically illuminate?
11.300’
What is the cabin pressure limit? (Max and min)
+ 9.0psi
- 1.0psi
