Oral: ECS Question Flashcards
Know
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 theprimary 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 offresh 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 getLanding 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 thecabin 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 < 50knots
•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 thingsthat 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…
1. Airplane is 500 AFE with both engines operating 2. Airplane is > 9,700 MSL with one engine operating
What happens if smoke is detected in the recirculation bay?
- Both recirculation fans deactivate
- Cargo recirculationfan 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…
1. Airplane stops climbing and begins a descent, and 2. Airplane has not climbed > 5,000 AFE or >10,000 MSL
