Systems-APU, Aural/Visual Warnings, Air conditioning and pneumatics Flashcards
At what cabin altitude will you get the amber “CABIN PRESS” message displayed on EICAS?
8,500 ft
Where does the exhaust air from the flight compartment get routed?
Under the floor and through the avionics compartment bay.
How does the temp control operate in normal mode?
Input from temp selector as well as duct and fan sensor.
How does the left pack distribute air?
60% cockpit
40% cabin
How does the right pack distribute air?
100% cabin
How is cabin pressure normally controlled?
- Automatically by the Cabin Pressure Controller ( CPC)
- The CPC electronically controls the outflow valves
How are the packs cooled?
From ram air intake at the bottom of the vertical tail.
When will the packs automatically go into “High Mode” when in flight?
When there is either an over pressure or an over temp.
What is set on the cabin pressure controller with the “A” knob?
Landing field elevation
If you need to return to your departure field after takeoff do you need to reset the “A” knob?
No; the CPC remembers the takeoff field elevation.
Which EICAS messages can be cleared from view? How?
Cautions-CAS Key of the ECP
Status Messages-STAT key of the ECP
What are the 5 items that can cause a T/O configure warning?
B-Brakes F-Flaps A-Autopilot S-Spoilers T-Trim
In what order are EICAS messages displayed?
In order of importance with the most recent failure at the top of each list.
- Warnings (Red)
- Cautions (Amber)
- Status (White)
When are caution messages inhibited?
During T/O and landing
Can advisory messages ever be hidden?
No
What happens when you push in the PWR/FUEL button?
- Activates APU fuel pump
- Opens fuel SOV and NEG G SOV
- Displays APU RPM and EGT on EICAS
How do we determine if the APU is having a hung start?
> 60 seconds to 30%
When does the green AVAIL light illuminate?
At 95%+4 sec
Except for fire how do determine why the APU auto-shutdown?
By looking at the APU trip indicators on the APU fault panel.
Which APU auto-shutdown does not have an associated EICAS message?
Overcurrent
Why do we wait 5 seconds to push the APU fire bottle?
To give the flapper valve on the APU enclosure time to close.
What is the maximum altitude for APU bleed air?
15,000ft
When shutting down the APU when do you push the PWR FUEL switch?
Once RPM is below 50% and EGT below 350c
What is the maximum altitude for APU electrical power?
20,000ft
Can the APU be used to restart an engine in the air?
Yes; only is dual engine failure
What issue will be associated with APU receiving fuel from the left tank?
When operating on the left tank there is no fuel cooling available. APU will eventually overheat.
Under heavy load how does the APU prioritize its workload?
Under heavy load the APU will close the LOAD CONTROL VALVE as needed to ensure continued electrical supply.
Max temp of APU bleed air
260c
Max APU EGT
731c
APU generator max load
30kVA
When the air conditioning is selected to CABIN the pax can manipulate the temperature _____ degrees above and below the temperature set on the cockpit overhead.
+- 7 degrees
What does CPAM stand for?
Cabin Pressurization Acquisition Module
What do CPAMs do?
Provide EICAS with
- cabin altitude info
- rate of change
- diff pressure
- CPAM status
*The DCUs use the higher value between CPAM 1 and CPAM 2
