Study Guide ECS Flashcards
What does the AMS use bleed air for?
- ECS (heating and 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 bleeds
- External Pneumatic Source
What is bleed air used for?
- ECS (heating and 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 located?
Lower fairing between the wings
What is the primary use for APU bleed air?
- ECS on the ground
- Engine starting on the ground
- Assist with engine start <15,000
Can engine bleed air flow back to the APU?
No, a check valve prevents back flow
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’s the purpose of the pre-cooler?
Cools the bleed air from the engines coming 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 left and right
- each engine provides air for it’s respective packs
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 crossbreed valve
What’s the ration of fresh air to recirculation air?
52% fresh, 48% recirculation
When are the circulation fans commanded off?
- Cockpit switch
- smoke detection in the recirculation bay
- DUMP button is pressed
- respective pack is commanded off
What keeps the 3 avionics E-Bays cool?
- FWD and MID 3 fans each pull air from cabin
- AFT natural air flow from cabin
When is the Emergency RAM Air Ventilation activated?
- Both packs commanded or failed 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 standby
Where does the CPC get Landing Field Elevation?
FMS or can be manually selected
