Air Management

Question 1

What does the AMS provide?

Answer 1

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

Question 2

What happens if the active channel fails on the AMS controller?

Answer 2

The other channel is able to control the entire AMS

Question 3

What provides air for the AMS?

Answer 3

• engine bleeds
• APU bleed
• external pneumatic source

Question 4

What is bleed air used for?

Answer 4

• ECS (heating and cooling)
• engine start
• engine and wing anti ice
• water pressure

Question 5

What is external pneumatic air used for?

Answer 5

• ECS on ground

- engine start on ground

Question 6

Where is the external ground source panel located?

Answer 6

Lower fairings between the wings

Question 7

What is the primary use for APU bleed air?

Answer 7

• ECS on the ground

- Engine start on the ground

Question 8

Can engine bleed air flow back to the APU?

Answer 8

No, a check valve prevents flow-back

Question 9

Where is bleed air tapped from the engines?

Answer 9

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

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

Question 10

What is normal pressure for any engine operation?

Answer 10

45 psi

Question 11

What is the purpose of the precooler?

Answer 11

Cools the bleed air coming from the engine to the AMS

Question 12

What cools the preschooler?

Answer 12

Ground - N1 fan

Question 13

What does the Overheat Detection System observe?

Answer 13

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

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 to detect the overheat

Question 15

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

Answer 15

• 2 independent packs (L and R)

- Each engine provides bleed air to its respective pack

Question 16

Can a single pack provide adequate temperature control and pressurization?

Answer 16

Yes, up to FL310

Question 17

Can a single bleed source power both packs?

Answer 17

Yes, through the crossbleed valve

Question 18

What is the ratio of fresh air to recirculated air?

Answer 18

52% fresh, %48 recirculated

Question 19

When are the recirculation fans commanded off?

Answer 19

• Cockpit switch
• Smoke detected in the recirc bay
• DUMP button
• Respective pack commanded off
• Fire detected in the cargo bay

Question 20

What keeps the 3 avionic EBAYs cool?

Answer 20

• FWD and CTR: 3 fans each pull air from cabin to bay

- AFT EBAY: Natural air flow from cabin to bay

Question 21

When is the emergency ram air ventilation activated?

Answer 21

• Both packs commanded off below 25,000 ft (via left side and electronically controlled)
• Ram air pressure greater than cabin pressure (via right side)

Question 22

How many channels on the cabin pressure control(CPC)?

Answer 22

2 channels, one active and one in standby mode

Question 23

Where does the CPC get landing field elevation?

Answer 23

FMS or can be manually selected

Question 24

What happens when the dump button is pressed?

Answer 24

• Commands both ECS packs OFF

- Opens OFV and raises the cabin to 12,400- ft at a rate of 2000 fpm

Question 25

Can the cabin altitude be raised above 12,400 ft?

Answer 25

- Yes, by use of the manual mode | - Cabin altitude will rise due to natural leak

Question 26

In manual mode will the cabin depressurize on landing?

Answer 26

No

Question 27

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

Answer 27

APU has priority if: - APU BLEED and XBLEED buttons are set to AUTO - APU BLEED and XBLEED valves are functioning normally - Wheel speed < 50 kts - REF ECSOFF and REF A/I not ALL, or single engine taxi

Question 28

When will the crossbreed 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 - APU BLEED button pushed out for engine start

Question 29

When and how will the system turn off an ECS pack?

Answer 29

- The AMS can command a pack off due to air supply source and bleed valve position, or: - The FADEC can send a signal to the AMS commanding pack off when it is required for engine performance

Question 30

When are ECS packs recovered?

Answer 30

The ECS packs are recovered at an altitude where the performance is no longer required (or in the case of two engines, TL is reduced below TOGA)

Question 31

What happens if smoke is detected in the recirculation bay?

Answer 31

- Both recirculated fans deactivate - Cargo recirculated fan deactivates - Cargo outflow balve closes

Question 32

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

Answer 32

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

Question 33

What color is the LFE on the EICAS?

Answer 33

- Green: FMS input | - Cyan: Manual input (plus and 'M' will be in front of LFE)

Question 34

What is the ABORT mode?

Answer 34

Cabin is selected 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