02_DSC-21 Air Conditioning/Pressurization/Ventilation

two ACSC (Air Conditioning System Controller)

• Air conditioning:

1. air to the primary heat exchanger

2. cooled air enters the compressor è higher pressure + Temperature

3. cooled again in the MAIN heat exchanger (water) and enters the turbine, where its expand => generator power for compressor and cooling air fan

• removal of energy during process reduces air temperature
• water separator system dries air before turbine section

• Ram Air: to remove smoke => ON: outflow valve opens about 50% when under automatic control and differential pressure less than 1 PSI  

• Hot Air pressure regulating valve: closed when: a) ducts overheat b) cockpit trim air valve fails c) both cabin trim air valves fail (remain open, even when forward or aft cabin air valve fails)

• Pack controller: closed when TO PWR is set + ldg gear compressed and ldg gear compressed and speed at or above 70 kts => open 20 s after below 70 kts

• Temperature sensors: a) in the cockpit b) lavatory extractions and galley ventilation 

18 bis 30 Grad 

ECAM (Electronic Centralized Aircraft Monitoring) 

Zone controller failure:

a) primary: secondary as backup => flow setting and optimized temperature regulation are not available è HOT AIR and TRIM AIR valves close

Zones are controlled to 24 Grad => Pack 1 cockpit Pack 2 cabin

     ALTN MODE appears in the ECAM (Electronic Centralized Aircraft Monitoring)

b) both: Optimazied and bacup are lost => packs delivery fixed temperature: 20 for PAX 1 and 10 for PAX 2

• Failure removes all info from ECAM COND, which then displays PACK REG

• Pack controllers:

Pimary: Regulation is not optimized and Pack flow is fixed at the previous setting

Both: As backup outlet temperature is controlled by the anti-ice valve  (5 and 30 degrees in max. of 6 min)

• Ecam signals are lost 

Air conditioning system controllers: 

One: no affect, second takes over 

Both: related pack is lost and hot air pressure regulating valve + trim air valves remain closed 

ACM (air cycle machine) 

• ACM (air cycle machine) failure: the affected pack may be operated in heat exchanger cooling mode 

Failure of the hot air pressure regulating valve:

Failed Open: no affect

Closed: optimized regulation is lost => trim valves to closed position => Pack1: cockpit pack2: Cabin 

• HOT AIR pushbutton: FAULT when overheat (over 88 degrees) => off when below 70 degrees or crew select off

• PACK pb: closed when: a) upstream pressure below min. b) compressor overheat c) engine start (when on IGN) N2 < 50% ==> on ground reopening of the valves is delayed for 30s to avoid a suppl. Pack closure cycle during second engine start

• Pack flow: low=80%, norm=100%, High=120%
• in single pack ops or APU => HI automatically
• if LOW and cooling demand not satisfied => automatically to 100%

In transit: the flapis partially open 

Inline-Amber: the flap is fully open on ground 

Inline Green: teh flap is fully open in flight 

Nr 1: amber when temperature is higher than 90 degrees 

highe rthan 230 degrees

pack flow => Amber when closed 

6. pack flow control valve:

a) Inline green: open

b) inline AMber: open, and disagrees with the control position

c) crossline green: fully closed

d) crossline amber: fully closed  and disagrees with the control position

In flight when RAM Air flap is not fully open and both pack flow control valves are closed 

when zone duct temperature is at 80 degrees

C = Cold valve fully closed

H= hot valve fully open 

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