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.
When will PACK valves open after start?
30sec or when mode switch to normal. APU will supply the PACKs
What temp is each increment on the temperature selctors?
2deg
18-30deg
Can you get low pressure ground conditioning unit?
Yes, air goes into the mixing unit.
What happens to PACK flow valve if overtemp?
Automatically closes.
What cabin Diff PX do you need for RAM air to supply?
Less than 1 psi
How are the cargo compartments heated?
Ambient air from cabin via Inlet Isolation Valve. Exits via Extraction Fan or via an isolation valve if there is diff px. Outlet Isolation Valve
Can have Trim air on some aircraft.
How is Cargo heating controlled?
Automatically via the Cargo Ventilation Controller, does both FWD and AFT
How many Ventilation systems are there?
2
Lavatory and Galley
Avionics
What happens in the Lavatory Galley Vent system?
Completely automatic
Extraction Fan takes air from them and puts it overboard.
No Controls or indications
Does the Battery Vent system have any controls or indications?
No
What is the Avionics Ventilation System?
Cool air to Avionics Compartment
Flight instruments
CB panels
What fans are involved in the Avionics Ventilation System?
Blower and Extractor Fans, Controlled by an Avionics Equipment Ventilation Controller
Where can you see Avionics Vent information?
On the Cab Press ECAM. VENT INLET OUTLET, normally white
Where is air taken for the Avionics Vent System?
From a Skin Air Inlet valve, out via Skin Air Extract. Both open is OPEN CIRCUIT config.
Inlet on left outlet right.
When do the Skin Air Valves close?
When the skin temperature is low enough. Closed Circuit Configuration.
What is the intermediate configuration?
A small flap will open on the Skin Outlet valve if Skin Temp is too high in flight.
What is the Closed Circuit Configuration?
Air is being cooled via a skin air heat exchanger. To cool avionics. Air is recirculated
Fault on the Blower light, what will happen?
Override Blower, Shuts off fan and allows air in from air conditioning duct.
Fault in Extract, what will happen?
Override Extract, Allows air in from the Air Cond system.
What happens if smoke in the Avionics Vent system?
Both FAULT lights. Closes Skin heat exchanger, closes blower fan, opens small vent in skin outlet valve and allows Air Cond air into the system.
