Air Management System Questions 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 on 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 air-flow from cabin to bay
When is the Emergency Ram Air Ventilation activated?
- Both packs commanded or failed OFF below 25,000 ft. MSL (via left side and electronically controlled)
- Ram air pressure greater than cabin pressure (via right side)
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
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
