AIRCONDITIONING Flashcards
(38 cards)
What types of air is provided to the cabin?
Fresh conditioned air and recirculated cabin air
How many zones are there in the pax compartment and in total?
6 in pax compartment labeled A - F
2 cargo (AFT and BULK)
F/D (Flight deck)
What sources can provide bleed air?
- Engines
- APU
- Ground source
Conditioned air can also be connected on the ground directly to the conditioned air manifold
What is the purpose of the recirculation fans?
To recirculate cabin air. This allows the packs to operate at a reduced capacity which saves fuel
How is each pack controlled?
Each pack is controlled by two redundant channels in one of two controllers. If one channel fail in a controller, control of the repective pack is continued automatically by the redundant channel in that controller
What would cause pack output to automatically decrease?
When demand for bleed air is high like during gear retraction and during certain phases of flight to reduce fuel consumption
On the ground, which is noiser, one or two packs?
One pack
What is the difference between the EICAS message PACK L/R and PACK MODE L/R?
PACK L/R: Means that the pack is inoperative
PACK MODE L/R: Means that the pack is in stand-by cooling mode
How is cooling achived in stand-by cooling mode?
Bleed air is passed through the ram air heat exchanger only and bypassing the ACM in that pack.
When does a pack in stand-by cooling mode shut down?
When is the only time that it doesn’t shut down?
At lower altitudes and with high OAT when ambient conditions do not permit cooling. Pack restarts automatically when altitude and temperature permits
If both packs are in stand-by cooling mode or if one pack failed and the other one is in standby cooling mode, the pack valve doesn’t close at lower altitudes or higher temperatures. Reason for this is to be able to maintain cabin pressurization.
From where does the Flight deck receive fresh conditioned air?
From the left pack
What is the consequence of a RECIRC FAN being switched off?
The packs operates at full capacity which means more air is needed from the Engines and fuel consumption increases 0,7% for each fan that is OFF
How many trim air systems are there?
Two (Left and Right)
What provides air to the left and right trim air system?
Air from the respective Engine. Air is tapped off Before the heat exchanger and mixed into the conditioned air manifold to mix with cool conditioned air
What is the max and min Master temp selector range?
18 - 29 deg C
What is the flight attendants range for cabin temp control?
+- 6 deg C
How can the flight deck temp be manually controlled?
By using the FLT DECK TEMP selector in the MAN setting
Which zone controls the pack output temperature?
The zone that is requireing the coolest temp
What is the default temp if control is lost?
24 deg C
After a failiure of both cabin temp controllers, how is pack flow achieved?
By the ASCPC controllers
Pack flow is modulated to achieve a pack outlet temp of between 5 - 43 deg C
Are the flight deck shoulder and foot warmers available on the ground?
No, only in flight
Where are the Upper and Lower RECIRC fans drawing air from and where are they recirculating it to?
Upper: Draws air from the area above the pax compartment and recirculates it back to the zone ducts after the conditioned air manifold
Lower: Draws air from under the floor area and recirculates the air into the conditioned air manifold
Describe the Equipment cooling normal operation
A supply fan draws air from the FWD cargo bay over temp and smoke sensors. Those sensors also detects fan failiures if no air is coming over them.
Air flows into the flight deck panels and Equipment racks from below.
Air is then drawn into the exhaust duct via a vent fan and back into the FWD cargo compartment.
There is another smoke detector after the vent fan to detect smoke from the avionics bay.
How is temp controlled in the FWD cargo compartment?
By valves that opens and close to direct more air into the compartment for heating or to send the air overboard before it reaches the compartment
