Flashcards in Air Conditioning Deck (34)
What is the purpose of the ram air?
An emergency ram air inlet ventilates the cockpit and cabin to remove smoke or if both packs fail.
What is the function of the mixer unit?
This unit mixes cold fresh air from the packs with the cabin air being recirculated through recirculation fans.
What is the function of the trim air valves?
These valves are electrically controlled by the air conditioning system controllers. The cockpit trim air valve and the cabin trim air valves adjust the temperature by adding hot air.
What is the function of the APU flow demand?
When the APU bleed valve is open the air conditioning system controller signals the APUs Electronic Control Box (ECB) to increase the APU flow output when any zone temperature demand cannot satisfied.
For which zones is an independent temperature control possible?
Cockpit fwd cabin and aft cabin.
Is a temperature control from the cabin possible?
Yes during cruise the cabin crew can modify each cabin zone temperature that is selected from the cockpit with a limited authority of +/- 2 5°C or +/-4 5°F.
What is the function of the pack flow control valve?
This valve regulates the air flow in accordance with signals received from the air conditioning system controllers.
What is the temperature selection range?
The temperature selection range is from 18°C (64°F) to 30°C (86°F).
Under which condition should the pack flow controller be set to LO?
With a low passenger load to reduce bleed air demand and improve fuel efficiency.
Under which circumstances delivers the air conditioning system high flow?
In single pack operation or when the APU is supplying bleed air.
Under which condition should the pack flow controller be set to HI?
With a high passenger load in hot conditions in order to help reduce the cabin temperature.
What happens to the pack flow control valves during engine start?
They automatically close.
How is the pack flow control valve controlled and operated?
The valve is electrically controlled and pneumatically operated.
The PACK FLOW controller is set to NORM and the ECAM display shows PACK FLOW to be high. How is this possible?
High flow is automatically selected regardless of PACK FLOW sel position because air is only being supplied by the APU.
In which cases closes the pack flow control valve?
The Pack flow control valve closes automatically in case of pack overheating engine starting or operation of the fire or ditching pushbutton.
What is the purpose of the hot-air pressure-regulating valve?
This pneumatically operated and electrically controlled valve regulates hot air pressure which is tapped upstream of the packs.
How can you operate the emergency ram air inlet valve?
The emergency inlet valve is controlled by the ram air pushbutton on the air cond panel. This pushbutton opens the ram air valve provided that ditching is not selected.
What happens if the Air Cycle Machine (ACM) fails?
The affected pack may be operated in heat exchanger cooling mode. Warm pre-conditioned bleed air enters the cooling path via the pack valve and goes to the primary heat exchanger. The main part of the cooled air goes directly downstream of ACM turbine though the bypass valve and the rest goes though the failed ACM.
Where are temperature sensors located?
In the cockpit for the cockpit zone in the lavatory extraction circuit and galley ventilation system for the cabin.
When does the hot-air pressure-regulating valve close automatically?
This valve closes automatically if the duct overheats the cockpit trim air valve fails or both cabin trim air valves fail.
How does the Air Conditioning System Controller configure its associated pack ram air inlet flap for takeoff and landing to avoid the ingestion of foreign matter?
TAKEOFF: Ram air inlet flap closes when takeoff power is set and the main landing gear struts are compressed. Ram air inlet flap re-opens after main landing gear strut extension. LANDING: Ram air inlet flap closes as soon as the main landing gear struts are compressed and speed is great than or equal 70 knots. Ram air inlet flap opens 20 seconds after speed <70 knots
What is the function of the HOT AIR pushbutton?
Control the hot air pressure regulating valves which controls the flow of hot air to the trim air valves. This hot air is mixed with the pack-conditioned air for zone temperature control
What does an amber "FAULT" light in the HOT AIR pushbutton indicate?
Duct Overheat - the hot air and trim air valves close automatically
Describe how the Air Conditioning System Controllers regulate temperature?
BASIC temperature regulation: Both packs produce the required outlet temperature determined by the lowest demanded zone temperature. OPTIMISED temperature regulation: Hot air is added to the individual zones by the trim air valves to maintain the desired zone temperatures
What occurs when both lanes of an Air Conditioning System controller fails?
The related pack is lost. The hot air pressure-regulating valve and associated trim air valve(s) close
What causes the Pack Flow Control valve to automatically close?
Upstream pressure below minimum. Pack overheat. Engine start sequence. Engine FIRE pushbutton on the related side pressed. DITCHING pushbutton selected
What would cause an amber "FAULT" light to illuminate in the PACK 1/2 pushbutton? (OOD)
Overheat - pack outlet. Overheat - compressor outlet. Discontinuity - switch position disagreement with pack flow control valve
What effect will the engine starts sequence have on the pack flow control valves?
The pack flow control valves will close automatically
The PACK FLOW selector has LO, NORM, and HI positions. What does this allow us to do?
Select pack flow rates representing LO 80%, NORM 100%, and HI 120% of norm