Study Guide ECS

Question 1

What does the AMS use bleed air for?

Answer 1

• ECS (heating and cooling)
• Engine start
• Pressurization
• Engine and wing anti-ice
• Water pressure
• Hot air leak detection

Question 2

How many AMS controllers are installed?

Answer 2

One controller with 2 channels which control the respective onside system

Question 3

What happens if a channel fails?

Answer 3

The remaining channel is able to control the entire AMS

Question 4

What provides air for the AMS?

Answer 4

• Engine bleeds
• APU bleeds
• External Pneumatic Source

Question 5

What is bleed air used for?

Answer 5

• ECS (heating and cooling)
• Engine start
• Engine and wing anti-icing
• Water pressurization

Question 6

What is external pneumatic air used for?

Answer 6

• ECS on the ground

- Engine start on the ground

Question 7

Where is the external ground source located?

Answer 7

Lower fairing between the wings

Question 8

What is the primary use for APU bleed air?

Answer 8

• ECS on the ground
• Engine starting on the ground
• Assist with engine start <15,000

Question 9

Can engine bleed air flow back to the APU?

Answer 9

No, a check valve prevents back flow

Question 10

Where is bleed air tapped from the engines?

Answer 10

• 6th and 10th stage compressors (EBV and HSV respectively)

- system alternates between valves to regulate an adequate and safe pressure

Question 11

What is normal pressure for any engine operation?

Answer 11

45 PSI

Question 12

What’s the purpose of the pre-cooler?

Answer 12

Cools the bleed air from the engines coming to the AMS

Question 13

What cools the pre cooler?

Answer 13

• Ground N1 fan

- Flight N1 fan or Ram air

Question 14

What does the Overheat Detection System (ODS) observe?

Answer 14

• Engine bleeds and packs
• APU bleed
• Plumbing for the wing and engine anti-icing system

Question 15

Do both loops have to function in order to detect an overheat condition?

Answer 15

Yes, but if one fails the other will work alone to detect the overheat.

Question 16

How many ECS packs are on the airplane? What provides air for the Packs?

Answer 16

• 2 independent packs left and right

- each engine provides air for it’s respective packs

Question 17

Can a single pack provide adequate temperature control and pressurization?

Answer 17

Yes, up to FL310

Question 18

Can a single bleed source power both packs?

Answer 18

Yes, through the crossbreed valve

Question 19

What’s the ration of fresh air to recirculation air?

Answer 19

52% fresh, 48% recirculation

Question 20

When are the circulation fans commanded off?

Answer 20

• Cockpit switch
• smoke detection in the recirculation bay
• DUMP button is pressed
• respective pack is commanded off

Question 21

What keeps the 3 avionics E-Bays cool?

Answer 21

• FWD and MID 3 fans each pull air from cabin

- AFT natural air flow from cabin

Question 22

When is the Emergency RAM Air Ventilation activated?

Answer 22

• 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)

Question 23

How many channels on the Cabin Pressure Control (CPC)?

Answer 23

2 channels, one active and one standby

Question 24

Where does the CPC get Landing Field Elevation?

Answer 24

FMS or can be manually selected

Question 25

What happens when the dump button is pressed?

Answer 25

- Commands both ECS packs OFF | - Opens OFV and raises the cabin to 12,400 at a rate of 2,000 FPM

Question 26

Can the cabin altitude be raised higher than 12,400?

Answer 26

- Yes, bu using manual mode | - Cabin altitude will rise due to natural leak

Question 27

In manual mode will the cabin depressurize on landing?

Answer 27

No

Question 28

What is the bleed system priority in flight?

Answer 28

- onside engine - opposite side engine - APU (if available)

Question 29

If engine and APU bleed air are available simultaneously, which has priority?

Answer 29

APU has priority if - Aircraft is on the ground - Wheel speed is <50 kts - Opposite engine bleed pressure is not enough for engine start

Question 30

When will the crossbreed valve automatically open?

Answer 30

- Only one side bleed source is available - Engine 2 start in the air - Engine 1 start in the air IF APU IS NOT AVAILABLE

Question 31

What are some things that will close the ECS packs?

Answer 31

- 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)

Question 32

When are ECS packs recovered?

Answer 32

- TL not at MAX, and - Airplane is 500 AFE with both engines operating - Airplane is >9,700 MSL with one engine operating

Question 33

What happens if smoke is detected in the recirc bay?

Answer 33

- Both recirc fans deactivate - Cargo recirc fan deactivates - Cargo outflow valve closes

Question 34

Where does the CPCS get cruise flight level & landing elevation from?

Answer 34

- FMS before takeoff or CPCS calculates using ambient pressure - LFE may be manually inputed

Question 35

What color is the LFE on the EICAS?

Answer 35

- Green in FMS mode | - Cyan in manual input (an M will be in front of LFE)

Question 36

What is the ABORT mode?

Answer 36

- 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