AIR CONDITIONING Flashcards
What is the purpose of the Ram Air in the pneumatic system?
To ventilate the cockpit and cabin to remove smoke or used as an air source if both packs fail
What is the purpose of the mixing unit in the airconditioning system?
To mix cold fresh air from the packs with recirculated cabin air
What is the purpose of the trim air valves?
They adjusts the temperature by adding hot air
For which cabin zones is independent temperature control possible?
Cockpit
Fwd cabin
Aft cabin
Is temperature control possible from the cabin?
Yes, temperature can be modified by +/- 2.5 deg C from that selected from the cockpit
At what temperature will the Hot Air Press Regulating Valve close?
88 deg C and opens again below 70 deg C
What is the min, max and medium (12 o’clock pos) temperature that the pilots can select for the cabin?
Min 18
Medium 24
Max 30
What is the purpose of the “Turbine Bypass Valve” in the air conditioning system?
To modulate the pack outlet temperature by removing air prior to the compressor and adding it downstream of the turbine
What is the purpose of the “Anit-ice Valve” in the air conditioning system?
It opens when ice is detected on the condenser. Adds hot pneumatic air tapped off before the primary heat exchanger. Adds the air downstream of the turbine to melt ice over the condenser
What is the purpose of the Pack Flow Control Valve?
To regulate airflow into the airconditioning system according to signals received from the pack controller
How is the Pack Flow Control Valve operated and controlled?
Pneumatically operated and Electrically controlled
Why should the Pack Flow Contoller switch be set to LO, if possible?
To reduce bleed air demand and improve fuel efficiency with a low passenger load
Under what circumstances and how can the airconditioning system deliver high flow rates, if needed?
When zone temperatures cannot be satisfied the APU can increase it’s speed and the engine can increase it’s idle power. Single pack operation could be a situation when this happens
When should the Pack Flow Control Switch be set to HI?
With hi passenger load in high ambient temperatures
What happens to the pack flow control valves during start?
They close automatically to have all air available for start
The Pack Flow Control Switch is set to NORM but the ECAM display shows PACK FLOW HI. How is this possible?
High flow is automatically selected regardless of switch position when APU is operating or for single pack operation.
It will also operate in NORM (100%) when switch is set to LO and cooling requirements can’t be met
For the Pack Flow Control Switch, what percentage air flow is commanded for the LO, NORM and HI positions?
LO = 80%
NORM = 100%
HI = 120 %
When would the Pack Flow Control Valves close automatically?
- Overheating
*Upstream pressure low - Engine starting
- Fire pb is is pressed
- Ditching pb is pressed
How do you operate the emergency ram air inlet valve?
By pressing the RAM AIR pb
Is there any case where the RAM AIR inlet valve would not open when the pb is pressed?
If the ditching switch is selected or press diff is more than 1psi
Where are the temperature sensors located for the cockpit and cabin airconditioning system?
In the cockpit for the cockpit zone and in the lavatory extraction circuit and galley ventilation system for the cabin
How is the airconditioning system controlled?
By 2 dual channel Pack Controllers and by 1 dual channel zone contoller
What happens to the RAM air inlet flap during take-off and landing? Why does this occur?
They close to reduce ingestion of foreign objects
During take-off it opens when airborne
During landing they close when weight is on the wheels and speed is above 70 kts. The flap opens again 20 seconds after speed is below 70 kts
What situations would cause the HOT AIR PRESS REG VALVE to close automatically?
If overheat is detected
The cockpit trim air valve fails
Both cabin trim air valves fail
Both lanes in ACSC 1 fails
What happens when the HOT AIR pb is selected to OFF?
The HOT AIR PRESS REG VALVE and the trim air valves closes
What does a FAULT light in the HOT AIR pb mean?
Duct overheat, and the hot air trim air valves closes automatically
Describe how the air flows through the packs?
Pneumatic air flows through the PACK FLOW CONTROL VALVE and then through the PRIMARY HEAT EXCHANGER.
Then through the compressor and up to the MAIN HEAT EXCHANGER.
Then flows through a RE HEATER and CONDENSOR to a H2O EXTRACTOR. From here air flows through the TURBINE and then to the mixing unit.
What will happen if the ACM (Air Cycle Machine) fails?
The affected pack will operate as a heat exchanger
Air goes through the Pack Flow Valve and the Primary Heat exchanger. The main part of the air goes through the turbine by-pass valve and the remaining air goes through the failed ACM
When is air conditioned air introduced into the Avionics Compartment?
- During smoke removal
- With a FAULT in the blower
Why would the mixing unit line on top of the bleed page be amber?
Pack Flow Control Valves and RAM AIR inlet are closed
What if you see PACK FAULT lights during pre-flight. Is this normal?
Yes, as there might not be any pressure from the APU or Engine Bleeds yet
Your aircraft has less than 141 pax. What Pack Flow setting should be selected?
LO, to save fuel
You select the RAM AIR to open, but it doesn’t open….what is the problem? What can you do to fix the problem?
The valve only opens if Delta Press is less than 1.0 psi. Basically you have to descend
What happens if a Pack Controller has a double lane/channel failure?
Related pack is lost
Hot air press reg valve closes
Trim air valve on that side closes
What is the purpose of the CABIN FANS?
To re-circulate cabin air to the mixing unit and then back to the cabin
What are the temperatures for the: COLD, MIDDLE and HOT position on the Cargo heat panel?
Cold = 5 deg C
Middle = 15 deg C
Hot = 26 deg C
How can you tell if GND LP air supply is removed before selecting APU BLEED pb to ON?
Turn off the CAB FANS pb
Open the airvent on the instrument panel and confirm no airflow
What is the purpose of the CABIN FANS?
To re-circulate cabin air to the mixing unit and then back to the cabin
