Air Management Flashcards
What does the AMS provide?
- ECS (heating and cooling)
- Engine start
- Pressurization
- Engine and wing anti ice
- Water pressure
- Hot air leak detection
What happens if the active channel fails on the AMS controller?
The other 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
What is external pneumatic air used for?
- ECS on ground
- engine start on ground
Where is the external ground source panel located?
Lower fairings between the wings
What is the primary use for APU bleed air?
- ECS on the ground
- Engine start on the ground
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 precooler?
Cools the bleed air coming from the engine to the AMS
What cools the preschooler?
Ground - N1 fan
What does the Overheat Detection System observe?
- Engine bleeds and packs
- APU bleed
- Plumbing for the wing and anti-ice 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 to the packs?
- 2 independent packs (L and R)
- 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, %48 recirculated
When are the recirculation fans commanded off?
- Cockpit switch
- Smoke detected in the recirc bay
- DUMP button
- Respective pack commanded off
- Fire detected in the cargo bay
What keeps the 3 avionic EBAYs cool?
- FWD and CTR: 3 fans each pull air from cabin to bay
- AFT EBAY: Natural air flow from cabin to bay
When is the emergency ram air ventilation activated?
- Both packs commanded off below 25,000 ft (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?
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 2000 fpm
Can the cabin altitude be raised above 12,400 ft?
- Yes, by use of the manual mode
- Cabin altitude will rise due to natural leak
In manual mode will the cabin depressurize on landing?
No
If engine and APU bleed air are available simultaneously on the ground, which has priority?
APU has priority if:
- APU BLEED and XBLEED buttons are set to AUTO
- APU BLEED and XBLEED valves are functioning normally
- Wheel speed < 50 kts
- REF ECSOFF and REF A/I not ALL, or single engine taxi
When will the crossbreed valve open automatically?
- Only one side bleed source is available
- Engine 2 start in the air
- Engine 1 start in the air if APU is not available
- APU BLEED button pushed out for engine start
When and how will the system turn off an ECS pack?
- The AMS can command a pack off due to air supply source and bleed valve position, or:
- The FADEC can send a signal to the AMS commanding pack off when it is required for engine performance
When are ECS packs recovered?
The ECS packs are recovered at an altitude where the performance is no longer required (or in the case of two engines, TL is reduced below TOGA)
What happens if smoke is detected in the recirculation bay?
- Both recirculated fans deactivate
- Cargo recirculated fan deactivates
- Cargo outflow balve closes
Where does the CPCS get cruise flight level and landing elevation from?
FMS before takeoff or CPCS calculates using ambient pressure
- LFE may be manually input
What color is the LFE on the EICAS?
- Green: FMS input
- Cyan: Manual input (plus and ‘M’ will be in front of LFE)
What is the ABORT mode?
Cabin is selected 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
