Air Management System Flashcards
What does the AMS use bleed air for?
- ECS (heating and cooling)
- Engine start
- Pressurization
- Engine and wing anti-ice
- Water pressure
- Hot air leak detection
The pressurization system consists of:
- Cabin outflow valve
- Statis pressure port
- Negative pressure relief valve
- Positive pressure relief valve
- Cabin pressure controller
Max differential pressure is:
8.7 PSI
When will the positive pressure relief valve open?
8.7psi
When will the negative pressure relief valve open?
-0.5psi
Max differential negative pressure is?
-0.5psi
How many AMS controllers are installed?
One controller with 2 channels which control the respective onside system
What happens if a channel fails>
The remaining channel is able to control the entire AMS
What provides air for the AMS?
- Engine bleeds
- APU bleed
- External pneumatic source
What is bleed air used for?
- ECS (heating and cooling)
- Engine start
- Engine and wing anti-ice
- Water pressure
In addition to air conditioning, what other functions does the ECS provide?
- Filtered cabin air recirculation
- Gaspers
- Fan air cooling for avionics
- Emergency ram air ventilation for clearing smoke from cockpit
How would an APU or engine bleed button show a detected leak?
An amber light illuminates on the button
What is external pneumatic air used for?
- ECS on the ground
- Engine start on the ground
The outflow valve can be modulated ___ or ___ .
Aeronautically, manually
Is manual pressure displayed on the MFD?
Yes, in psi.
When will the ground cart connection be displayed on the MFD?
Only when the ground cart is actually connected
The negative pressure relief valve opens when
If cabin pressure drops below outside pressure
The positive pressure relief valve (safety valve) is ___ driven
Pneumatically
When can the flight attendant control the temp in the passenger cabin?
Only when the pilot places the PAX CABIN TEMP knob to the ATTND position
How does the flight attendant know if the temp setting know allows her to adjust the temp?
An ENABLED led turns on whenever the pilot selects the ATTND in the cockpit
What does the ATTND position do on the PAX CABIN knob?
Switches over the cabin temperature control to the flight attendant control panel
What colors are used for set and actual temp in the cockpit and cabin on the ECS Synoptic page?
- CYAN is set
- GREEN is actual
Where is the external ground source panel located?
Lower fairing between the wings
What is the primary use for APU bleed air?
- ECS on the ground
- Engine starting on the ground
- Electrical source (
What happens when the BLEED 1 (2) pushbutton is out?
Allows automatic operation of the bleed valve by the AMS controller
What happens when the BLEED 1 (2) pushbutton is out?
Manually closes the engine bleed valve
What would be an indication of a detected engine bleed leak?
An AMBER light illuminating in the respective BLEED button
Are there lights in the BLEED buttons?
- Yes
- White stripe: closes the bleed valve
- Amber stripe - illuminates when a leak is detected
How many bleed regulating valves are in each engine?
2, one high stage (HSV) and one engine bleed valve (EBV)
Where is bleed air tapped from the engines?
- 6th and 10th stage compressors (EBV and HSV respectively)
What is the normal engine bleed pressure?
45psi
What is the purpose of the pre-cooler?
Cools the bleed air coming from the engine to the AMS
What cools the pre-cooler?
- Ground: N1 fan
- Flight: N1 fan or ram air
What protects the bleed system from an overheat condition?
The overheat detection system
What does the Overhear Detection System (ODS) observe?
- Engine bleeds, packs and air conditioning ducts
- APU bleed
- Plumbing for the wing an engine anti-icing system
How many loops does the ODS use?
2 loops within 6 sensor locations
Do both loops have to function in order to detect an overheat condition?
Yes, but if one fails the other will work along to detect the overheat
How many ECS packs are on the airplane? What provides air for the pack?
- 2, L and R
- Each engine provides bleed air to its respective pack
Can a single pack provide adequate temp control and pressurization?
Yes, up to FL 310
What happens when the PACK 1 (2) pushbutton switch is in?
Allows automatic operation of the pack valve by the AMS controller
What happens when the PACK 1 (2) pushbutton switch is out?
Manually closes the respective PACK valve
What happens when the APU BLEED pushbutton is in?
Allows automatic operation of the APU bleed valve by the AMS controller
What does pushing out the APU BLEED button do?
Closes the APU BLEED valve
Can a single engine bleed source provide adequate bleed to operate both packs?
Yes, through the cross-bleed valve
Wat is the ratio of fresh air to recirculated air?
52% fresh to 48% recirculated air
When are the recirculation fans commanded off?
- Cockpit switch
- smoke detected in the recirc bay
-DUMP button is pressed - Both packs are commanded OFF
Cargo bay fire signal activates - Fire test (shuts fans off momentarily)
- On ground cabin warm-up mode when the APU is the bleed source
How many recirc fans recirculate air back into the cabin and flight deck?
2
What is affected by turning the RECIRC fans OFF at the gate?
Cooling air stops in the forward and center E-bays
What does pushing in the RECIRC button do?
Allows auto operation. Turns on both recirc fans IAW system logic
Pushing out the RECIRC button turns off
Both recirc fans
What happens to the recirc fans when he DUMP button is pushed, or smoke is detected in the recirc bays
The recirc fans are commanded to OFF
What keeps the three avionics E-Bays cool?
- FWD and CTR E-Bay: 3 vent fans each pull air from cabin to bay
- After E-bay: Natural air flow from cabin to bay
Which SPDAs are located in which E-Bays?
SPDA-1 is in FWD E-Bay, SPDA-2 is in CTR E-Bay
The AFT E-bay has no fans. How is it cooled?
From air flowing from PAX cabin and expelled toward recirc bay
What is the normal position of the gasper shutoff valve?
CLOSED, allowing gasper air. It opens when the gasper air supply exceeds 95 degrees F which prevents hot air from blowing on the PAX during cabin heating
When is the emergency am air ventilation commanded open?
Any time the airplane is in flight and both air condition packs commanded or failed OFF and airplane altitude is less than 25,000ft
What controls the RAM AIR check valve?
Only pressure, It will open when pressure within the ram air circuit is greater than cabin pressure
Where does the CPC get landing field elevation (LFE)
FMS or can be manually selected
Can the cabin altitude be raised higher than 12,400ft?
- Yes, by using manual mode
- Cabin altitude will rise due to natural leak
In manual mode will cabin depressurize on landing
No
What is the bleed system priority in flight?
- Onside engine
- Opposite side engine
- APU (if available)
Does the bleed system priority change on the ground?
Yes, as long as:
- Wheel speed
Can the APU bleed be used for the anti ice system?
No
When will the APU bleed valve open?
- APU switch is set to AUTO
- APU bleed is available
- No APU and left bleed duct leak
- Left engine bleed is unavailable
- Anti ice system not requested (or anti ice system requested ON and anti-ice system is failed)
Can engine bleed airflow to the APU when the engine is running?
No. The APU check valve will prevent engine bleed air flow to the APU
When will the crossbleed valve automatically open?
- One side provides manifold pressure and there is not a bleed air source on the opposite side
- Engine #2 start in the air
- APU bleed OFF for engine 1 start in the air
- APU bleed button is pushed out for main engine start
What happens when the XBLEED button on the panel is pushed out?
It manually closes the crossbleed
What happens when the XBLEED button is in?
Allows automatic operation of the crossbleed valve by the AMS controller
What side of the XBLEED does the GND CONN air connect?
Right side
What side of the XBLEED does the GND CONN air connect?
Left side
What happens when 1 side provides manifold pressure and there is not a bleed air source on the opposite side when the XFEED pushbutton is in?
The crossed valve is commanded open
What are some things that will close the ECS packs?
- Any engine start if APU is the bleed source (both packs close)
- Engine start and there is WOW (both packs (close)
- Respective bleed system duct leak
- Bleed air source not available for the pack
- Respective PACK button is OFF
Respective engine is starting, there is no WOW and the opposite engine is not starting - ECS OFF signal during T/O or Go-around for specific situations
When are ECS packs recovered automatically if there were commanded off during takeoff roll?
TL not at MAX and any of the following occur:
- Thrust lever reduction
- Airplane is 500 ft above takeoff field attitude with both engines operating
- Airplane is > 9700ft MSL, for takeoff fields at 8000ft or below with one engine operating
- Airplane is above 15000ft for takeoff fields above 8000ft and one engine inoperative
Do the packs turn on automatically after takeoff if they are commanded off during the takeoff roll?
Yes, after the takeoff phase
How many smoke detectors are mounted in the recirc bay?
Only one and if smoke is detected then both recirc fans are commanded off
What happens if smoke is detected in the recirc bay?
- Both recirc fans deactivate
- Cargo recirc fan deactivates
- Cargo outflow valve closes
Which caro bays have ventilation fans?
Forward
What occurs within the forward cargo bay in the event f smoke detection?
- Vent fans turn off
- Cargo outflow valve closes
- This contains the halon within the FWD cargo compartment
The DUMP switch is used for?
- Emergency evacuation
- Fast cabin depressurization
- Smoke evacuation
What type of switch is the DUMP button?
Its a guarded momentary pushbutton
What happens when the dump button is pressed?
- Commands both ECS packs OFF
- Opens OFV and raises the cabin to 12,400 ft at a rate of 2,000fpm. If the cabin is above 12,400ft when the DUMP is activated the cabin altitude will rise due to natural leak. The cabin can be depressurized to higher altitudes using the manual mode
Will the DUMP button work when the pressurization switch is in the manual or landing field control mode?
No it only works in AUTO mode
Why does the DUMP button have a red raised border around it?
So you can find it in case of smoke in the cockpit
What prevents the cabin from negative pressure?
The negative pressure relief valve (NPRV)
Does the positive pressure relief valve require electrical power to operate?
No
When cabin altitude is equal to or higher than ___ ft a ___ color CABIN ALTITUDE HI message appears on the EICAS
9700, red
An amber CABIN DIFF PRESS FAIL message appears on the EICAS when the cabin different ill is higher that ___ PSID or lower than ___ PSID
8.5psi, -0.3psi (according to study guide, not sure this is right)
An amber PRESN AUTO FAIL message appears on the EICAS means that both auto controller channels have failed. Can the cabin pressurization be controlled?
Yes, manually via the pressurization panel
Cabin pressure indications normally displayed where?
EICAS
What seven flight modes are target cabin pressure and pressure rates calculated for?
Ground, taxi, takeoff, climb, cruise, descent, abort
What target cabin pressure is used on the ground?
0.01psi differential lower than sensed cabin pressure, Rate changes at +5–ft/min increasing and -300ft/min decreasing
What are the two climb modes?
Internal (FMS inputs failed) and external (FMS inputs available)
What are the normal pressure rates of change in the flight mode?
+500ft/min when increasing and -300ft/min when decreasing
If you lose the manual controller for pressurization, how do you control aircraft pressurization?
You have a secondary manual controller
The MAN mode position allowed manual control of?
Outflow valve
Is the pressurization system still in AUTO mode when operated manually?
Yes
How can you determine the position of the outflow valve?
There is a pointer on the outflow valve position indicator on the environmental synoptic page on the MFD
When does the outflow valve close?
Gear down and engines providing takeoff thrust
What must you do to manually control the cabin altitude?
The pressurization MODE Selector knob must be in MAN
Why do we put the CABIN ALT selector knob in the STOP position?
Normal operating position, allows automatic operation of the system
What are the DOWN.UP positions used for on the CABIN ALT selector knob?
Manually closes.opens the outflow valve to decrease/increase cabin altitude at a rate of 50 fpm
Under what conditions will the DOWN or UP positions of CABIN ALT knob function?
Only when the MODE control knob is in MAN. These positions provide control over the outflow valve
What us the LFE CTRL selector position on the pressurization MODE selector knob used for ?
Allows manual input of the landing field elevation
At what point do you see the landing field election on the DU screen?
After the flight plan is closed out
If you lose automatic input to the Pressurization Controller what will the landing field election show?
Cyan colored LFE until you move the LFE CNTRL at which point you will also get a cyan “M”
While on LGE mode are you still in auto mode or foes the system revert to manual?
Remains in automatic mode
How would you manually control the LFE?
With the LFE selection knob momentarily selected to the DOWN/UP position decrease/increase the LFE in 100ft increments
What color is the LFE on the EICAS?
Green: FMS input
Cyan: Manual input
What happens to the landing fields elevation (LFE) in the ABORT mode?
During the ABORT mode the cabin pressure is scheduled back to the takeoff altitude
How many channels does the cabin pressure controller have?
- The CPC has 2 independent automatic channels that alternate after each flight
- If one fails the other takes over
What does an AMBER pressurization display mean?
Cautionary operating range
What are the four pressurization indications viewed on EICAS?
- Cabin altitude
- Rate up/down
- PSI
- LFE
Where does the CPCS get cruise flight level and landing election and foes weight from?
- FMS before takeoff or CPCS calculates using albeit pressure
- LFE may be manually input
What will it do if no information is provided to it?
It regulates in the backup mode using temperatures
What are the normal differential pressures used?
7.8psi up to 37,000 and 8.3psi above 37,000 (it uses info from the FMS or sensed ambient pressure)
What is the most dangerous type of pressurization
Slow
If is critical after you notice a depressurization to do what?
Put on your oxygen mask
You have climbed above FL180 after departure and find it necessary to return to the departure airport, how do you reconfigure the pressurization system?
Change the destination in the flight plan to the departure airport
When the engine and APU bleed are available simultaneously and the airplane is not he ground or the opposite engine bleed pressure is below the min for engine start, which has priority?
The APU supply bleed
What is the ABORT mode?
Cabin is scheduled to the takeoff altitude if:
- Airplane stops climbing; cruise mode was not activated and
- Airplane has not climbed >5,000 AFE or >10,000MSL
