21 - Air Conditioning Flashcards
What are the main air sources for the ACS?
Bleed air from engines, the Auxiliary Power Unit (APU), or a ground air supply.
What is the role of the mixer unit in the ACS?
Combines conditioned air from the packs with recycled air and mixes hot air from the bleed system to achieve the selected temperature.
How does the emergency ram air system function?
If both packs fail, the emergency ram air inlet opens when differential pressure is below 2 PSI, providing external air to the mixer unit for ventilation and cooling.
What does the Supplemental Cooling System (SCS) cool?
Galleys and the Avionics Ground Cooling Unit.
Which CPIOMs control the SCS?
CPIOMs H43 and H44.
What happens if one cooling unit in the SCS fails?
The system performance is degraded but continues operating with reduced capacity.
How is temperature in the cabin controlled?
Adjusted via the CABIN selector on the AIR panel or by the cabin crew through the Flight Attendant Panels (FAPs).
What is the purpose of the AIR FLOW selector?
Adjusts airflow from the packs and recirculated cabin air, with automatic and manual modes to suit passenger load and altitude.
How does the trim air system enhance temperature regulation?
Adds hot air from the bleed system to the mixed air for precise temperature control in specific zones.
What is the temperature regulation capability of the bulk cargo compartment?
It can only heat, not cool, and uses an electrical heater to maintain the desired temperature.
Which cargo compartment can be cooled, and how is it controlled?
The forward cargo compartment can be cooled using air from the ACS, controlled via the FWD TEMP REGUL selector on the CARGO AIR COND panel.
What happens during a SMOKE AFT/BULK CARGO SMOKE alert?
Isolation valves close automatically, and the heater and extraction fan stop to contain the smoke.
What does the PACK FAULT light indicate?
Indicates:
- Disagreement between pack valve positions and commands.
- Pack overheating or failure.
- Bleed air leak.
Which component adjusts airflow based on passenger load and altitude?
The pack controllers.
What information is displayed on the BLEED SD page?
Displays pack valve states, pack airflow rates, and bleed air supply status.