ECS Questions

Question 1

What does the AMS use bleed air for?

Answer 1

ECS
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 bleed
APU bleed
External pneumatic

Question 5

What is bleed air used for?

Answer 5

ECS
Engine start
Engine and wing anti-ice
Water pressurization

Question 6

What is external pneumatic air used for?

Answer 6

ECS and external air start

Question 7

Where is the external ground source panel 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
Electrical

Question 9

Can engine bleed air flow back to the APU?

Answer 9

No

Question 10

What is normal bleed pressure for engine operation?

Answer 10

45 psi

Question 11

What is the purpose of the pre-cooler?

Answer 11

Cools the bleed air coming from the engine to AMS

Question 12

What cools the pre-cooler?

Answer 12

Ground N1 fan

Flight N1 fan or ram air

Question 13

What does the overheat detection system (ODS) observe?

Answer 13

Engine bleed and packs
APU bleed
Plumbing for wing and engine anti-ice

Question 14

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

Answer 14

Yes, but if one fails the other will work alone

Question 15

Can a single pack provide adequate temperature control and pressurization?

Answer 15

Yes, up to FL310

Question 16

Can a single bleed source power both packs?

Answer 16

Yes, through the crossbleed valvle

Question 17

What is the ratio of fresh air to recirc air?

Answer 17

52/48

Question 18

When are the recir fans commanded off?

Answer 18

Cockpit switch
Smoke detected in recirc bay
DUMP button is pressed
Respective pack is commanded off

Question 19

What keeps the three avionic e-bays cool?

Answer 19

FWD & CTR e-bay: Three fans pull air from cabin to bay

AFT e-bay: Natural air-flow from cabin to bay

Question 20

When is the emergency ram air ventilation activated?

Answer 20

Both packs commanded or failed OFF below 25,000ft (via left side)
Ram air pressure greater than cabin pressure (via right side)

Question 21

How many channels on the CPC?

Answer 21

2 channels, one active and one in standby

Question 22

Where does the CPC get LFE?

Answer 22

FMS can be manually selected

Question 23

What happens when the dump button is pressed?

Answer 23

Commands both ECS packs OFF

Opens the OFV and raises the cabin to 12,400ft at a rate of 2,000 fpm

Question 24

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

Answer 24

Yes, by using manual mode

Cabin altitude will rise due to natural leak

Question 25

In manual mode will the cabin depressurize on landing?

Answer 25

No

Question 26

What is the bleed system priority in flight?

Answer 26

Onside engine, opposite side engine, APU

Question 27

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

Answer 27

APU has priority if: Aircraft is on ground Wheel speed

Question 28

When will the crossbleed valve open automatically?

Answer 28

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 29

What are some things that will close the ECS packs?

Answer 29

``` 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 ```

Question 30

When are ECS packs recovered?

Answer 30

TL not at MAX, and Airplane is 500 AFE with both engines operating Airplane is > 9700 MSL with one engine operating

Question 31

What happens if smoke is detected in the recirc bay?

Answer 31

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

Question 32

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

Answer 32

FMS before TO or CPCS calculates using ambient pressure | LFE may be input manually

Question 33

What color is LFE on the EICAS?

Answer 33

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

Question 34

What is ABORT mode?

Answer 34

Cabin scheduled back to TO altitude if | - airplane stops climbing and begins a descent and airplane has not reached 5000 AFE or 10000 MSL

Question 35

Explain the Emergency Ram Air Ventilation System

Answer 35

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

Question 36

What is the RAID system

Answer 36

``` 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 ```