Air Cond Systems Flashcards
How does Hot Bleed air enter the PACK?
Through Pack flow control valve
What happens in the PACK?
2 heat exchanges (ram air inlet and outlet flaps) and an air cycle machine produce cooler air, sub zero temps can be achieved. Bypass valve allows warmer air to be mixed, bypasses ACM and last heat exchanger.
What controls the valves
The ACS controller
What happens to the Ram air inlet during take-off?
Closes
Where is the air from PACKs sent?
To mixing unit
What is shown on ECAM for PACKS?
PACK flow (Valve pos)
Comp outlet temp
Bypass valve position
Pack outlet temp
How many outputs from the Mixing Unit?
3
Cockpit
Fwd Cabin
Aft Cabin
How many ACS controllers?
2
each has 2 lanes
One active and one stby
Both fail PACK lost
How is warm air added after the mixing unit?
Via 3 Trim Air Valves via hot air valve, regulates and acts as a shut-off valve.
Where is Hot air for the trim system taken?
Downstream from the Pack Valves so if they are closed then no trim air.
Which ACS controls which Trim air?
1 controls Hot Air Valve and Trim air for Cockpit
2 Controls FWD and AFT cabin
What are the Cabin Fans?
Recirc fans, take air back to mixing unit, no indication of these. Can switch off on OHP
On ground with APU bleed on which PACKS are supplied?
Both, via the Xbleed
What is the 12 o clock position on the zone temperature knobs?
24deg
When do the PACK valves close during start?
When ENG Mode selector to IGN/Start. Will open again after 30sec if no start.