Air Management System (AMS) Flashcards
What does the AMS use bleed air for?
ECS (heating & cooling)
Engine start
Pressurization
Engine and wing anti-ice
Water pressure
Hot air leak detection
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 & cooling)
Engine start
Engine and wing anti-icing
Water pressurization
What is external pneumatic air used for?
ECS on the ground
Engine start on the ground
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 (< FL330)
Assist with engine start (< FL210)
Bleed source for pressurization
Heating, and cooling (< 15,000 ft. MSL)
Can engine bleed air flow-back to the APU?
No. A check valve prevents flow-back
Where is bleed air tapped from the engines?
6th and 10th stage compressors (EBV and HSV respectively)
System alternates between valves to regulate an adequate and safe pressure
What is normal pressure for any engine operation?
45 psi
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 does the Overheat Detection System (ODS) observe?
Engine bleeds and packs
APU bleed
Plumbing for the wing and engine anti-icing system
Do both loops have to function in order to detect an overheat condition?
Yes, but if one fails the other will work alone to detect the overheat
How many ECS packs are on the airplane? What provides air for the packs?
2 independent packs (Pack 1 and Pack 2); Each engine provides bleed air to its respective pack
Can a single pack provide adequate temperature control and pressurization?
Yes, up to FL310
Can a single bleed source power both packs?
Yes, through the crossbleed valve
What is the ratio of fresh air to recirculated air?
52% fresh air to 48% recirculated air
When are the recirculation fans commanded off?
Cockpit switch
Smoke detected in the recirc bay
DUMP button is pressed
Respective pack is commanded off
What keeps the 3 avionic E-BAYs cool?
FWD & CTR E-BAY 3 fans each pull air from cabin to bay
AFT E-BAY Natural airflow from cabin to bay
When is the Emergency Ram Air Ventilation activated?
Both packs commanded or failed OFF below 25,000 ft. MSL
Ram air pressure greater than cabin pressure at any altitude
How many channels on the Cabin Pressure Control (CPC)?
2 channels, one active and one in standby mode
Where does the CPC get Landing Field Elevation (LFE)?
FMS or can be manually selected
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 2,000 fpm
Shuts off both recirculating fans
Can the cabin altitude be raised higher than 12,400 ft.?
Yes, by using manual mode
Cabin altitude will rise due to natural leak
In manual mode will the cabin depressurize on landing?
No
What is the bleed system priority in flight?
Onside engine
Opposite side engine
APU (if available)
If engine and APU bleed air are available simultaneously, which has priority?
APU has priority if Aircraft is on the ground
Wheel speed < 50 knots
Opposite engine bleed pressure is not enough for engine start
When will the crossbleed valve automatically open?
Only one side bleed source is available
Engine 2 start in the air
Engine 1 start in the air if APU is not available
What are some things that will close the ECS packs?
Any engine start if APU is the bleed source
Engine start on the ground
Respective bleed system duct leak
Bleed air source not available for the pack
TL set to MAX on takeoff
REF A/I set to ALL on takeoff
REF ECS set to OFF on MCDU (APU is OFF)
When are ECS packs recovered?
TL not at MAX, and Airplane is 500 AFE with both engines operating
Airplane is > 9,700 MSL with one engine operating
What happens if smoke is detected in the recirculation bay?
Both recirculation fans deactivate
Cargo recirculation fan deactivates
Cargo outflow valve closes
Where does the CPCS get cruise flight level & landing elevation from?
FMS before takeoff or CPCS calculates using ambient pressure; LFE may be manually inputted
What color is the LFE on the EICAS?
Green FMS input
Cyan Manual input (an ‘M’ will be in front of LFE)
What is the ABORT mode?
Cabin is scheduled back to the takeoff altitude if Airplane stops climbing and begins a descent, and Airplane has not climbed > 5,000 AFE or > 10,000 MSL
