ECS Questions Flashcards
What does the AMS use bleed air for?
ECS 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 bleed
APU bleed
External pneumatic
What is bleed air used for?
ECS
Engine start
Engine and wing anti-ice
Water pressurization
What is external pneumatic air used for?
ECS and external air start
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
Can engine bleed air flow back to the APU?
No
What is normal bleed pressure for engine operation?
45 psi
What is the purpose of the pre-cooler?
Cools the bleed air coming from the engine to AMS
What cools the pre-cooler?
Ground N1 fan
Flight N1 fan or ram air
What does the overheat detection system (ODS) observe?
Engine bleed and packs
APU bleed
Plumbing for wing and engine anti-ice
Do both loops have to function in order to detect an overheat condition?
Yes, but if one fails the other will work alone
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 valvle
What is the ratio of fresh air to recirc air?
52/48
When are the recir fans commanded off?
Cockpit switch
Smoke detected in recirc bay
DUMP button is pressed
Respective pack is commanded off
What keeps the three avionic e-bays cool?
FWD & CTR e-bay: Three fans 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 25,000ft (via left side)
Ram air pressure greater than cabin pressure (via right side)
How many channels on the CPC?
2 channels, one active and one in standby
Where does the CPC get LFE?
FMS can be manually selected
What happens when the dump button is pressed?
Commands both ECS packs OFF
Opens the OFV and raises the cabin to 12,400ft at a rate of 2,000 fpm
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 the cabin depressurize on landing?
No
What is the bleed system priority in flight?
Onside engine, opposite side engine, APU
If engine and APU bleed air are available simultaneously, which has priority?
APU has priority if:
Aircraft is on ground
Wheel speed
When will the crossbleed 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
What are some things that will close the ECS packs?
Any engine start if APU is bleed source Engine start on ground Respective bleed system duct leak Bleed air source not available for pack TL set to MAX on TO REF A/I set to ALL on TO REF ECS set to OFF on MCDU with APU off
When are ECS packs recovered?
TL not at MAX, and
Airplane is 500 AFE with both engines operating
Airplane is > 9700 MSL with one engine operating
What happens if smoke is detected in the recirc bay?
Both recirc fans deactivate
Cargo recirc fan deactivates
Cargo outflow valve closes
Where does the CPCS get cruise and flight level and landing elevation from?
FMS before TO or CPCS calculates using ambient pressure
LFE may be input manually
What color is LFE on the EICAS?
Green FMS input
Cyan manual input (an M will be in front of LFE)
What is ABORT mode?
Cabin scheduled back to TO altitude if
- airplane stops climbing and begins a descent and airplane has not reached 5000 AFE or 10000 MSL
Explain the Emergency Ram Air Ventilation System
Provided in case of pack shutdown for smoke removal or pack failure
Ram air ventilation valve is commanded open only if both packs are commanded/failed off and altitude is less than 25,000ft
Emergency ram air check valve will be open whenever pressure in the ram air circuit is greater than cabin pressure
What is the RAID system
Modulates to provide cooling air to pack Controlled by AMS RAIDs open when: Airplane is on ground and until 17,500 ft during climb Below 17,000 ft during descent Press dump button activated RAT deployed Anti-ice activated
