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