Air Conditioning - Pressuirisation Flashcards
How many packs are there?
Two (air cycle machines ACM)
Where are the packs located?
In the unpressurised aft equipment bay
What does the recirc fan do?
Mixed cabin air with the conditioned air from the packs
If there is a dual pack (ACM) failure what will provide air to the flight comp and cabin?
Emergency Ram Air ventilation system
What does the ECU do to the recirc fan?
When recirc fan is on it starts slow speed until the ECU automatically selected high speed when req
If one pack is off what speed does the recirc fan operate at?
Slow speed
Temperature Gauge selector positions?
Cabin duct supply temp
Cabin temp
Flight comp duct supply temp
Automatic pack operation when AUTO switch is selected allows for what?
ECU controls the FCSOV and pack bypass valve which regulates the cabin and flight Comp temperatures using the temp control knobs
Manual operation of pack temp what happens?
ECU only controls only the pack bypass Valve. The FCSOV will be full open
What valves are closed when packs are turned off?
FCSOV
Pack bypass SOVs
Turbine shut off valves
Both ACMs shutdown
Air flow distribution with 2 ACMs?
Flight Comp receives 50% left pack
Cabin receives 50% left pack
Cabin revives 100% right pack
Therefore cabin receives approx 75% of the airflow
Single pack operation how much capacity is it providing?
70% of the two pack operation
Does there flight compartment temperature selector effect the cabin temp?
Yes because half the air from the left pack goes to the cabin
Is upper and lower vent selection available in FA control panel?
No only on the classic
When will the inlet and outlet valves close in the aft baggage compartment?
Loss of electrical power or if smoke is detected
Is the avionics cooling system automatic for normal and abnormal operation?
Yes
How many avionics fans are there?
3
Fan 1 and 2 and a standby fan
If two avionics fan fails what can we see?
FANS FAIL in white on the ED
AVIONICS caution light illuminated only on ground not in air
When will a pack shut down?
Selected OFF
ECU built in test detects unacceptable condition
CABIN PACK HOT
FLT COMP PACK HOT
CABIN DUCT HOT
FLT COMPT DUCT HOT
When will a CABIN PACK HOT or FLT COMPT PACK HOT caution light extinguish?
Until condition has cleared and the switch is in the OFF position
External ground air port?
Aft right side
Pressurisation area goes from? Front to back
Forward pressure bulkhead to aft pressure dome
How many outflow valves?
3
What are the outflow valves called?
Forward safety valve
Aft safety valve
Aft outflow valve
Pressurisation system modes?
Auto
Manual
Emergency/ smoke removal
Dump
Pressurisation confirm is the primary function of the electrically operated…?
Aft outflow valve
The forward outflow safety valve main purpose?
Emergency operation or smoke removal from flight comp
What prevents an aircraft pressurising on ground?
Power lever angle less than 60 degrees means aft outflow valve is positioned fully open