Environmental Control System (ECS) Flashcards
(33 cards)
How many Air conditioning packs are there?
2
Where does the left pack provide bleed air to?
Flight deck and last 4 rows
Where does the right pack provide bleed air to?
The cabin and cargo areas
What does the RECIRC FAN switch do when positioned to on?
Air is filtered and re-circulated into the flight deck and cabin for greater efficiency.
On the ground, if actual cabin temperature differs from selected temperature in flight deck by more than __ degrees, the ACSC will increase pack flow to decrease the time for pull up/down.
10 degrees
Outflow valves are controlled by ___. One for each cabin pressure controller (CPC) and one that will react during manual pressurization.
3 DC motors
What two computers control all aspects of bleed air and air conditioning while in AUTO.
ACSC (Air conditioning system controller)
AILC (Anti ice leak controller)
What is the key difference in AUTO and MANUAL temperature control?
Auto has protection, manual does not.
What are the indications and what would happen you would see after pressing the EMER DEPRESS at FL250?
- 8500 - Caution message
- 10,000 - Warning message
- 14,000 +/- 300 ft PAX O2 masks drop
- 14,500 +/- 500 ft Cabin press is locked by limiter.
Max cabin altitude is set, auto or manual inputs overridden. Outflow valve driven open by manual DC motor. Active CPC is instructed to close outflow valve at cabin ALT of 14,500 +/- 500.
How many pressure controllers are there? Are they always active?
2 CPCs (Cabin Pressure Controllers)
Only one is active at a time and they alternate.
When do the CPCs change automatically?
Weight off wheels + 3 minutes, when one computer fails
What happens when both CPCs fail?
Enters isobaric hold mode
How can you manually change CPCs
Double press (PRESS CONT) button on the cabin pressure panel
If the CPAM-like microprocessor should fail, which CPAM functions will be lost?
Passenger signs will not illuminate and O2 masks will not drop automatically
Following a CPAM-microprocessor failure, which of the CPAM functions will still be functioning and which component will take over these functions?
One of the CPCs will take over and will take care of displaying the CABIN ALT caution and warning messages at 8500 and 10,000. Will also engage the cabin limiter mode as well at 14,500 +/-500.
What is the maximum cabin altitude allowed by the outflow valves?
14,500 +/- 500 so 15,000.
How would you cause the cabin pressure to INCREASE manually?
Set manual mode and push “down” on the switch.
Why do we not need any sort of pressure regulating pack valve?
45 PSI is regulated by the PRSOVs and LCV
How is Pack output regulated by the ACSC?
Temperature control valve and Ram air regulating valve
In AUTO mode when will the Packs switch bleed air sources from APU to the engines?
Approach BIT/Takeoff BIT
When you command warmer or colder air from the Pack, what process takes place to change the temperature of pack output air?
Temp control valve and ram air regulating valve actuate to control temp
What malfunction will cause the PACK FAULT switchlight to illuminate?
Pack failure in AUTO mode
Which cargo compartment is pressurized and air conditioned and where does the conditioned air come from?
Both are pressurized, aft only receives conditioned air from the recirculated cabin air on Pack 2 from an inlet SOV. If failed then it comes from the mixing manifold.
What occurs automatically following a smoke or overheat detection in AFT cargo bay?
Heater will cut off and intake/exhaust SOVs close. EICAS message will display indicating AFT cargo fire.
